Aggression in Men - Hormone Levels Are a Key - NYTimes.com Aggression in Men: Hormone Levels Are a Key By DANIEL GOLEMAN Published: July 17, 1990 WHEN men are domineering and intensely competitive, it may be just another case of raging hormones, specifically the male sex hormone testosterone, researchers say. Scientists have long linked abnormally high levels of testosterone to an unusually early involvement with sex and drug use and to certain violent crimes, like particularly vicious rapes. But now a series of new findings show that high testosterone levels play a role in the normal urge for the upper hand. Those men who are most likely to try to dominate in a social situation, be it in a prison yard or a board room, are likely to have higher testosterone levels than their peers, new data show. Scientists caution against placing too much stock in the importance of hormones like testosterone in human affairs, since so many other factors, from childhood experiences to social status, shape the expression of a given behavior like dominance or competitiveness. ''This doesn't mean that people can't be dominant or aggressive without high testosterone,'' said Dr. Robert Rose, a psychiatrist at the University of Minnesota medical school.

''A woman, of course, can be as competitive as a man, even though her testosterone levels are much lower.'' Scientists emphasize that the effects of hormones on human behavior are small relative to social and psychological factors, showing up most clearly in studies of large numbers of people. And Dr. Rose is among a group of scientists who are skeptical that the hormone is a strong and direct cause of specific human behavior. He cites a series of studies, most involving small numbers of people, that have posted contradictory findings. ''In animals behavior like mating, nesting and aggression is much more tightly linked to hormones than is true in humans,'' Dr. Rose said. ''In humans hormones only set the stage, while social factors determine if and how they are expressed.'' Still, a growing body of new evidence portrays a distinct role for testosterone among men jockeying for power. High testosterone levels have long been known to typify the dominant males in groups of primates like baboons, and in unusual groups of men like prison inmates and hospitalized psychiatric patients. But the recent research has found the same differences in men who seek social dominance in normal realms of life. ''Hormonal secretions create a propensity for certain behaviors,'' Dr. Rose said.

''Testosterone seems most strongly linked to competitiveness and dominance.'' The findings apply only to men. After puberty, testosterone levels in men are about 10 times higher than in women. ''The highest testosterone level in women tends to fall within the low range for men, so that the hormone is a far greater factor for men than women,'' said Dr. Richard Udry, head of a center for population study at the University of North Carolina, who is studying the effects of testosterone on sexuality. But researchers agree with Dr. Rose that other factors can make women just as competitive as men. The newest and strongest evidence about the effect of testosterone comes from a study of 1,706 men in the Boston area, aged 39 to 70. The men were selected at random as part of a larger study on aging. Those who agreed to participate were interviewed in their homes and given psychological tests, and blood samples were taken. Those who had higher levels of testosterone and related hormones had a personality profile that researchers described as ''dominant with some aggressive behavior.'' ''The picture we get is of a man who attempts to influence and control other people, who expresses his opinions forcefully and his anger freely, and who dominates social interactions,'' said John B.

McKinlay, a psychologist at the New England Research Institute in Watertown, Mass., who was on the research team. The study, which will be published in Psychosomatic Medicine, is considered significant because it is the first to examine so many randomly chosen men. Most studies of testosterone in humans have been on small numbers in select populations, like prison inmates. Other studies, Dr. McKinlay noted, have found that men high in the trait of social dominance tend to rise to positions of leadership in business and other organizations. But for many others, some traits associated with testosterone present an obstacle to success. Exactly how a man's high testosterone level is expressed depends in part on his social class, another new study has found. For men of lower social and economic status, it is likely to show up as a readiness for fights, a history of minor crimes, and chronic trouble with parents, teachers and peers in childhood. But that is not true at higher social and economic rungs, where the display of dominance is more subdued, researchers say.

Study of Vietnam Veterans The findings are from data collected by the Federal Centers for Disease Control from 4,462 Vietnam veterans who were studied starting in 1985 to assess long-term effects of military service. The men's social and economic standing was rated as high if they fell into the top half of the United States population in both income and education level, and low if they fell into the bottom half. An analysis of data on their testosterone levels was reported in the current issue of Psychological Science by James Dabbs Jr., a psychologist at Georgia State University. 1 Estrogen, The Female Sex Hormone, May Influence Aggression In Both Men And Women Estrogen, The Female Sex Hormone, May Influence Aggression In Both Men And Women Jan 22, 2015 12:32 PM By Susan Scutti Close E-mail Generally, we think of estrogen as a female sex hormone, but during the 1970s it was discovered that testosterone, the male sex hormone, can be converted in the brain into estrogen. Now, a new study suggests estrogen may serve an important function in the brain, one that even encourages violence… at least, in mice.

Estrogen-producing nerve cells, UC San Francisco researchers discovered, exert specific effects on aggressive behavior in both male and female mice. “Though social behaviors — marking of territory, recognizing potential mates, successfully mating, fighting — seem quite ‘seamless’ when we observe them, this study shows that different neural systems control quite distinct, specific components of these behaviors,” Dr. Nirao Shah, senior author of the study, stated in a press release . Working with adult mice, Shah and a team of researchers depleted estrogen-producing nerve cells — also known as aromatase-expressing (aromatase+) cells — in a brain region known as the posterodorsal medial amygdala, or MeApd. This structure, in which aromatase+ cells make up 40 percent of the total neurons, is vital to social and reproductive behavior. In fact, it is linked to the olfactory bulb in the forebrain where it receives smell and pheromonal information commonly used by mice to identify other mice and to respond appropriately. Researchers show how estrogen-producing nerve cells exert specific effects on aggressive behavior in both male and female mice.

Pier-Luc Bergeron Using a genetic technique, the researchers eliminated the small cluster of aromatase+ cells from the MeApd in males, then in females. At first, the genetically modified male mice behaved as they normally do: They marked their territory, and they recognized, courted, and successfully mated with females. However, when these mice encountered an unfamiliar male in their territory, they showed a dramatically altered social style. Typically, male mice rattle their tails and then attack a same-sex intruder. The mice without aromatase+ neurons, though, showed less tail-rattling, and then it took them longer to mount an attack. In fact, the researchers saw a direct relation between the number of aromatase+ cells that had been eliminated and the lag time before an attack. Strangely, when these genetically modified mice finally did attack, the aggressiveness of their fighting resembled that of normal males. In females, the consequences of depleted aromatase+ cells only played out after they’d given birth. The genetically modified females responded to male mice in all the usual ways, but then, strangely, they seemed to lack the normal level of maternal aggression.

Generally, female mice with nursing pups will attack unfamiliar male mice, which are known to kill rival males' pups. However, these genetically modified females were slow to attack while nursing. Like the genetically modified males, though, they became indistinguishable from normal female mice once the fighting commenced. "In theory, these estrogen-producing neurons could have controlled any part of social behavior, or all social behaviors, but we found they control only a very small component of aggression," said Elizabeth K. Unger, a graduate student in the Shah lab and first author of the study. "And considering females do not need these cells to produce estrogen, it was quite surprising to find that these cells play a similar role in both males and females." Source: Unger EK, Burke KJ, Yang CF, et al. Medial Amygdalar Aromatase Neurons Regulate Aggression in Both Sexes. Cell Reports. 2015. About hormone therapy | Cancer Research UK About hormone therapy About hormone therapy Find out about hormone treatment for prostate cancer, when you have it and possible side effects. What it is Hormones occur naturally in your body. They control the growth and activity of normal cells. Testosterone is a male hormone mainly made by the testicles.

Prostate cancer depends on testosterone to grow. Hormone therapy blocks or lowers the amount of testosterone in the body. This can lower the risk of an early prostate cancer coming back when you have it with other treatments. Or it can shrink an advanced prostate cancer or slow its growth. When you have it Hormone therapy with radiotherapy You have this if: your cancer hasn’t spread but is at a high risk of coming back, e.g. the cancer has grown through the covering (capsule) of your prostate (stage 3) you have a very high prostatic specific antigen (PSA) level you have a high Gleason score You might have hormone therapy before, during and after radiotherapy. Doctors usually recommend that you have the treatment for between 3 months and 3 years. How long depends on the risk of your cancer coming back and how many side effects you get. You might have it with other treatments such as high frequency ultrasound treatment or internal radiotherapy.

Hormone therapy alone Hormone treatment is also a treatment if: the cancer is too advanced to have treatment with the aim to cure it you can’t have surgery or radiotherapy because of other health problems you don’t want radiotherapy or surgery You normally carry on taking hormone therapy for as long as it is working. Your doctor might suggest you have intermittent therapy. This is when you have treatment for 6 to 12 months and then have a break for a few months. You then start treatment again and have another break With intermittent therapy, you may have fewer side effects. At present the evidence is that intermittent treatment is not worse than having hormone treatment all the time. Talk to your doctor about this. Advanced cancer Hormone therapy is also a treatment for cancers that have spread to another part of the body. You might have it with chemotherapy such as docetaxel. Treatment if your cancer comes back Hormone therapy is also a treatment if your cancer comes back after having radiotherapy. Types of hormone treatment Drugs you have as injections The injections work by blocking messages from a gland in the brain that tell the testicles to produce testosterone.

There are two types: luteinising hormone (LH) blocker (agonists) for example leuprorelin (Prostap) and goserelin acetate (Zoladex) gonadotrophin releasing hormone (GnRH) blockers, for example degarelix (Firmagon) Luteinising hormone You have these as injections, they include: leuprorelin (Prostap) – you have this every 4 weeks or 12 weeks goserelin acetate (Zoladex) – you have this every 4 weeks or 12 weeks buserelin (Suprefact) – you have this as an injection 3 times a day for 7 days and then a nasal spray 6 times a day triptorelin (Decapeptyl) – you have this once a month, 3 monthly or 6 monthly At first, the injections may make your symptoms worse. This is called tumour flare. Your doctor will give you an anti androgen tablet to take for the first 4 to 6 weeks of your treatment with the LH blocker to stop the tumour flare. Gonadotrophin This is the other type of injection.

There is currently only one type called degarelix (Firmagon). When you first start treatment, you have 2 injections on the same day. Then you have one injection a month. There is no risk of tumour flare with this treatment. Anti androgen tablets These tablets stop testosterone from your testicles getting to the cancer cells. Examples of anti androgens include: bicalutamide (Casodex) – you take it once a day flutamide (Drogenil) – 3 times a day enzalutamide (Xtandi) – once a day Flutamide and bicalutamide are less likely to cause erection problems and other side effects than leuprorelin (Prostap) or goserelin (Zoladex). But they are more likely to cause breast swelling and tenderness. Enzalutamide is a treatment for men who have already had other types of hormone therapy and chemotherapy with docetaxel (Taxotere) that is no longer working. Abiraterone tablets The trade name for abiraterone is Zytiga. It is a type of hormone therapy that blocks an enzyme called cytochrome p17.

Without this enzyme, the testicles and other body tissue can't make testosterone. It is a tablet you take every day. You might have abiraterone if you have advanced prostate cancer and have already had other types of hormone therapy and chemotherapy with docetaxel (Taxotere) that is no longer working. There are two main ways to stop the body producing testosterone: drug treatment surgery Drug treatment is the usual way to stop your body producing testosterone. You have drug treatment as tablets or injections. Surgery to remove your testicles (orchidectomy) isn’t a common way of lowering the amount of testosterone you produce. You usually only have surgery to remove your testicles if you need your testosterone reduced urgently. For example if your cancer has spread to your bones and is pressing on your spinal cord, your doctors might want to reduce the amount of testosterone quickly. Your doctors may also suggest surgery as an option if you don't want to have treatment with medicines. Find out about surgery to remove your testicles Checking your hormone therapy is working You’ll have regular blood tests to check the level of a protein called prostate specific antigen (PSA). PSA is a protein made by both normal and cancerous prostate cells.

It is in the blood in small amounts in all men, unless they have had their prostate gland completely removed. While the hormone therapy is working, the level of PSA should stay stable or may go down. But if prostate cancer cells are starting to grow and develop, the level of PSA may go up. Then your doctor may need to change your treatment. They will discuss this with you. Side effects Side effects of hormone therapy are due to the low levels of testosterone in your body. Some are common to all hormone therapies for prostate cancer. Some effects vary from drug to drug. The main side effects are: erectile problems (impotence) Hormones & Behavior | Noba Hormones & Behavior By Randy J. Nelson The Ohio State University The goal of this module is to introduce you to the topic of hormones and behavior. This field of study is also called behavioral endocrinology, which is the scientific study of the interaction between hormones and behavior. This interaction is bidirectional: hormones can influence behavior, and behavior can sometimes influence hormone concentrations. Hormones are chemical messengers released from endocrine glands that travel through the blood system to influence the nervous system to regulate behaviors such as aggression, mating, and parenting of individuals.

 Share Define the basic terminology and basic principles of hormone–behavior interactions. Explain the role of hormones in behavioral sex differentiation. Explain the role of hormones in aggressive behavior. Explain the role of hormones in parental behavior. Provide examples of some common hormone–behavior interactions. Introduction This module describes the relationship between hormones and behavior. Many readers are likely already familiar with the general idea that hormones can affect behavior. Students are generally familiar with the idea that sex-hormone concentrations increase in the blood during puberty and decrease as we age, especially after about 50 years of age. Sexual behavior shows a similar pattern. Most people also know about the relationship between aggression and anabolic steroid hormones, and they know that administration of artificial steroid hormones sometimes results in uncontrollable, violent behavior called “roid rage.” Many different hormones can influence several types of behavior, but for the purpose of this module, we will restrict our discussion to just a few examples of hormones and behaviors. For example, are behavioral sex differences the result of hormones, the environment, or some combination of factors? Why are men much more likely than women to commit aggressive acts? Are hormones involved in mediating the so-called maternal “instinct”?

Behavioral endocrinologists are interested in how the general physiological effects of hormones alter the development and expression of behavior and how behavior may influence the effects of hormones. This module describes, both phenomenologically and functionally, how hormones affect behavior. To understand the hormone-behavior relationship, it is important briefly to describe hormones. Hormones are organic chemical messengers produced and released by specialized glands called endocrine glands . Hormones are released from these glands into the blood, where they may travel to act on target structures at some distance from their origin. Hormones are similar in function to neurotransmitters , the chemicals used by the nervous system in coordinating animals’ activities. However, hormones can operate over a greater distance and over a much greater temporal range than neurotransmitters (Box 1). Examples of hormones that influence behavior include steroid hormones such as testosterone (a common type of androgen), estradiol (a common type of estrogen), progesterone (a common type of progestin ), and cortisol (a common type of glucocorticoid) (Table 1, A-B). Several types of protein or peptide (small protein) hormones also influence behavior, including oxytocin , vasopressin, prolactin , and leptin.

Table 1-A: Prominent Hormones That Influence Behavior Table 1-B: Prominent Hormones That Influence Behavior Hormones coordinate the physiology and behavior of individuals by regulating, integrating, and controlling bodily functions. Over evolutionary time, hormones have often been co-opted by the nervous system to influence behavior to ensure reproductive success. For example, the same hormones, testosterone and estradiol, that cause gamete (egg or sperm) maturation also promote mating behavior. This dual hormonal function ensures that mating behavior occurs when animals have mature gametes available for fertilization. Another example of endocrine regulation of physiological and behavioral function is provided by pregnancy. Estrogens and progesterone concentrations are elevated during pregnancy, and these hormones are often involved in mediating maternal behavior in the mothers. Not all cells are influenced by each and every hormone. Rather, any given hormone can directly influence only cells that have specific hormone receptors for that particular hormone. Cells that have these specific receptors are called target cells for the hormone. The interaction of a hormone with its receptor begins a series of cellular events that eventually lead to activation of enzymatic pathways or, alternatively, turns on or turns off gene activation that regulates protein synthesis.

The newly synthesized proteins may activate or deactivate other genes, causing yet another cascade of cellular events. Importantly, sufficient numbers of appropriate hormone receptors must be available for a specific hormone to produce any effects. For example, testosterone is important for male sexual behavior. If men have too little testosterone, then sexual motivation may be low, and it can be restored by testosterone treatment. However, if men have normal or even elevated levels of testosterone yet display low sexual drive, then it might be possible for a lack of receptors to be the cause and treatment with additional hormones will not be effective. How might hormones affect behavior? In terms of their behavior, one can think of humans and other animals conceptually as comprised of three interacting components: (1) input systems (sensory systems), (2) integrators (the central nervous system), and (3) output systems, or effectors (e.g., muscles). Hormones do not cause behavioral changes. Rather, hormones influence these three systems so that specific stimuli are more likely to elicit certain responses in the appropriate behavioral or social context. In other words, hormones change the probability that a particular behavior will be emitted in the appropriate situation ( Nelson, 2011 ).

This is a critical distinction that can affect how we think of hormone-behavior relationships. We can apply this three-component behavioral scheme to a simple behavior, singing in zebra finches. Only male zebra finches sing. If the testes of adult male finches are removed, then the birds reduce singing, but castrated finches resume singing if the testes are reimplanted, or if the birds are treated with either testosterone or estradiol. Although we commonly consider androgens to be “male” hormones and estrogens to be “female” hormones, it is common for testosterone to be converted to estradiol in nerve cells (Figure 1). Thus, many male-like behaviors are associated with the actions of estrogens! Indeed, all estrogens must first be converted from androgens because of the typical biochemical synthesis process. If the converting enzyme is low or missing, then it is possible for females to produce excessive androgens and subsequently develop associated male traits. It is also possible for estrogens in the environment to affect the nervous system of animals, including people (e.g., Kidd et al., 2007 ). Again, singing behavior is most frequent when blood testosterone or estrogen concentrations are high.

Males sing to attract mates or ward off potential competitors from their territories. Figure 1: Biochemical Pathway for Steroid Hormone Synthesis: It is important to note that testosterone (an androgen) can be converted to another androgen, DHT, or an estrogen, estradiol. Too much or too little of the converting enzymes can influence brain and behavior. Although it is apparent from these observations that estrogens are somehow involved in singing, how might the three-component framework just introduced help us to formulate hypotheses to explore estrogen’s role in this behavior? By examining input systems, we could determine whether estrogens alter the birds’ sensory capabilities, making the environmental cues that normally elicit singing more salient. If this were the case, then females or competitors might be more easily seen or heard. Estrogens also could influence the central nervous system. Neuronal architecture or the speed of neural processing could change in the presence of estrogens. Higher neural processes (e.g., motivation, attention, or perception) also might be influenced. Finally, the effector organs, muscles in this case, could be affected by the presence of estrogens.

Blood estrogen concentrations might somehow affect the muscles of a songbird’s syrinx (the vocal organ of birds). Estrogens, therefore, could affect birdsong by influencing the sensory capabilities, central processing system, or effector organs of an individual bird. We do not understand completely how estrogen, derived from testosterone, influences birdsong, but in most cases, hormones can be considered to affect behavior by influencing one, two, or all three of these components, and this three-part framework can aid in the design of hypotheses and experiments to explore these issues. How might behaviors affect hormones? The birdsong example demonstrates how hormones can affect behavior, but as noted, the reciprocal relation also occurs; that is, behavior can affect hormone concentrations. For example, the sight of a territorial intruder may elevate blood testosterone concentrations in resident male birds and thereby stimulate singing or fighting behavior. Similarly, male mice or rhesus monkeys that lose a fight decrease circulating testosterone concentrations for several days or even weeks afterward. Comparable results have also been reported in humans. Testosterone concentrations are affected not only in humans involved in physical combat, but also in those involved in simulated battles. For example, testosterone concentrations were elevated in winners and reduced in losers of regional chess tournaments.

The expectation of events can influence one’s hormonal activity. How do you think yours is affected if you anticipate going on a date with a romantic interest soon? [Image: KESUPRODuction, CC BY-ND 2.0, People do not have to be directly involved in a contest to have their hormones affected by the outcome of the contest. Male fans of both the Brazilian and Italian teams were recruited to provide saliva samples to be assayed for testosterone before and after the final game of the World Cup soccer match in 1994. Brazil and Italy were tied going into the final game, but Brazil won on a penalty kick at the last possible moment. The Brazilian fans were elated and the Italian fans were crestfallen. When the samples were assayed, 11 of 12 Brazilian fans who were sampled had increased testosterone concentrations, and 9 of 9 Italian fans had decreased testosterone concentrations, compared with pre-game baseline values ( Dabbs, 2000 ). In some cases, hormones can be affected by anticipation of behavior. For example, testosterone concentrations also influence sexual motivation and behavior in women.

In one study, the interaction between sexual intercourse and testosterone was compared with other activities (cuddling or exercise) in women ( van Anders, Hamilton, Schmidt, & Watson, 2007 ). On three separate occasions, women provided a pre-activity, post-activity, and next-morning saliva sample. After analysis, the women’s testosterone was determined to be elevated prior to intercourse as compared to other times. Thus, an anticipatory relationship exists between sexual behavior and testosterone. Testosterone values were higher post-intercourse compared to exercise, suggesting that engaging in sexual behavior may also influence hormone concentrations in women. Sex Differences Hens and roosters are different. Cows and bulls are different. Men and women are different. Even girls and boys are different. Humans, like many animals, are sexually dimorphic (di, “two”; morph, “type”) in the size and shape of their bodies, their physiology, and for our purposes, their behavior. The behavior of boys and girls differs in many ways. Girls generally excel in verbal abilities relative to boys; boys are nearly twice as likely as girls to suffer from dyslexia (reading difficulties) and stuttering and nearly 4 times more likely to suffer from autism.

Boys are generally better than girls at tasks that require visuospatial abilities. Girls engage in nurturing behaviors more frequently than boys. More than 90% of all anorexia nervosa cases involve young women. Young men are twice as likely as young women to suffer from schizophrenia. Boys are much more aggressive and generally engage in more rough-and-tumble play than girls ( Berenbaum, Martin, Hanish, Briggs, & Fabes, 2008 ). Many sex differences, such as the difference in aggressiveness, persist throughout adulthood. For example, there are many more men than women serving prison sentences for violent behavior. The hormonal differences between men and women may account for adult sex differences that develop during puberty, but what accounts for behavioral sex differences among children prior to puberty and activation of their gonads? Hormonal secretions from the developing gonads determine whether the individual develops in a male or female manner. The mammalian embryonic testes produce androgens, as well as peptide hormones, that steer the development of the body, central nervous system, and subsequent behavior in a male direction. The embryonic ovaries of mammals are virtually quiescent and do not secrete high concentrations of hormones.

In the presence of ovaries, or in the complete absence of any gonads, morphological, neural, and, later, behavioral development follows a female pathway. Sex differences in appearance are often more pronounced in nonhuman animals than in humans. Male birds particularly, for example roosters, tend to have physical features that differ from the females and also differ significantly in size. [Image: John Cudworth] Gonadal steroid hormones have organizational (or programming) effects upon brain and behavior ( Phoenix, Goy, Gerall, & Young, 1959 ). The organizing effects of steroid hormones are relatively constrained to the early stages of development. An asymmetry exists in the effects of testes and ovaries on the organization of behavior in mammals. Hormone exposure early in life has organizational effects on subsequent rodent behavior; early steroid hormone treatment causes relatively irreversible and permanent masculinization of rodent behavior (mating and aggressive). These early hormone effects can be contrasted with the reversible behavioral influences of steroid hormones provided in adulthood, which are called activational effects. The activational effects of hormones on adult behavior are temporary and may wane soon after the hormone is metabolized.

Thus, typical male behavior requires exposure to androgens during gestation (in humans) or immediately after birth (in rodents) to somewhat masculinize the brain and also requires androgens during or after puberty to activate these neural circuits. Typical female behavior requires a lack of exposure to androgens early in life which leads to feminization of the brain and also requires estrogens to activate these neural circuits in adulthood. But this simple dichotomy, which works well with animals with very distinct sexual dimorphism in behavior, has many caveats when applied to people. If you walk through any major toy store, then you will likely observe a couple of aisles filled with pink boxes and the complete absence of pink packaging of toys in adjacent aisles. Remarkably, you will also see a strong self-segregation of boys and girls in these aisles. It is rare to see boys in the “pink” aisles and vice versa. The toy manufacturers are often accused of making toys that are gender biased, but it seems more likely that boys and girls enjoy playing with specific types and colors of toys. Indeed, toy manufacturers would immediately double their sales if they could sell toys to both sexes.

Boys generally prefer toys such as trucks and balls and girls generally prefer toys such as dolls. Although it is doubtful that there are genes that encode preferences for toy cars and trucks on the Y chromosome, it is possible that hormones might shape the development of a child’s brain to prefer certain types of toys or styles of play behavior. It is reasonable to believe that children learn which types of toys and which styles of play are appropriate to their gender. How can we understand and separate the contribution of physiological mechanisms from learning to understand sex differences in human behaviors? To untangle these issues, animal models are often used. Unlike the situation in humans, where sex differences are usually only a matter of degree (often slight), in some animals, members of only one sex may display a particular behavior. As noted, often only male songbirds sing. Studies of such strongly sex-biased behaviors are particularly valuable for understanding the interaction among behavior, hormones, and the nervous system. A study of vervet monkeys calls into question the primacy of learning in the establishment of toy preferences ( Alexander & Hines, 2002 ).

Female vervet monkeys preferred girl-typical toys, such as dolls or cooking pots, whereas male vervet monkeys preferred boy-typical toys, such as cars or balls. There were no sex differences in preference for gender-neutral toys, such as picture books or stuffed animals. Presumably, monkeys have no prior concept of “boy” or “girl” toys. Young rhesus monkeys also show similar toy preferences. If you think back to the toys and clothing you played with and wore in your youth, do you think they were more a result of your hormonal activity or the choices that society and your parents made for you? [Image: jmtimages, CC BY-NC-ND 2.0, What then underlies the sex difference in toy preference? It is possible that certain attributes of toys (or objects) appeal to either boys or girls. Toys that appeal to boys or male vervet or rhesus monkeys, in this case, a ball or toy car, are objects that can be moved actively through space, toys that can be incorporated into active, rough and tumble play. The appeal of toys that girls or female vervet monkeys prefer appears to be based on color.

Pink and red (the colors of the doll and pot) may provoke attention to infants. Society may reinforce such stereotypical responses to gender-typical toys. The sex differences in toy preferences emerge by 12 or 24 months of age and seem fixed by 36 months of age, but are sex differences in toy preference present during the first year of life? It is difficult to ask pre-verbal infants what they prefer, but in studies where the investigators examined the amount of time that babies looked at different toys, eye-tracking data indicate that infants as young as 3 months showed sex differences in toy preferences; girls preferred dolls, whereas boys preferred trucks. Another result that suggests, but does not prove, that hormones are involved in toy preferences is the observation that girls diagnosed with congenital adrenal hyperplasia (CAH), whose adrenal glands produce varying amounts of androgens early in life, played with masculine toys more often than girls without CAH. Further, a dose-response relationship between the extent of the disorder (i.e., degree of fetal androgen exposure) and degree of masculinization of play behavior was observed.

Are the sex differences in toy preferences or play activity, for example, the inevitable consequences of the differential endocrine environments of boys and girls, or are these differences imposed by cultural practices and beliefs? Are these differences the result of receiving gender-specific toys from an early age, or are these differences some combination of endocrine and cultural factors? Again, these are difficult questions to unravel in people. Even when behavioral sex differences appear early in development, there seems to be some question regarding the influences of societal expectations. One example is the pattern of human play behavior during which males are more physical; this pattern is seen in a number of other species including nonhuman primates, rats, and dogs. Is the difference in the frequency of rough-and-tumble play between boys and girls due to biological factors associated with being male or female, or is it due to cultural expectations and learning? If there is a combination of biological and cultural influences mediating the frequency of rough-and-tumble play, then what proportion of the variation between the sexes is due to biological factors and what proportion is due to social influences? Importantly, is it appropriate to talk about “normal” sex differences when these traits virtually always arrange themselves along a continuum rather than in discrete categories?

Sex differences are common in humans and in nonhuman animals. Because males and females differ in the ratio of androgenic and estrogenic steroid hormone concentrations, behavioral endocrinologists have been particularly interested in the extent to which behavioral sex differences are mediated by hormones. The process of becoming female or male is called sexual differentiation . The primary step in sexual differentiation occurs at fertilization. In mammals, the ovum (which always contains an X chromosome) can be fertilized by a sperm bearing either a Y or an X chromosome; this process is called sex determination . The chromosomal sex of homogametic mammals (XX) is female; the chromosomal sex of heterogametic mammals (XY) is male. Chromosomal sex determines gonadal sex . Virtually all subsequent sexual differentiation is typically the result of differential exposure to gonadal steroid hormones. Thus, gonadal sex determines hormonal sex, which regulates morphological sex. Morphological differences in the central nervous system, as well as in some effector organs, such as muscles, lead to behavioral sex differences. The process of sexual differentiation is complicated, and the potential for errors is present. Perinatal exposure to androgens is the most common cause of anomalous sexual differentiation among females.

The source of androgen may be internal (e.g., secreted by the adrenal glands) or external (e.g., exposure to environmental estrogens). Turner syndrome results when the second X chromosome is missing or damaged; these individuals possess dysgenic ovaries and are not exposed to steroid hormones until puberty. Interestingly, women with Turner syndrome often have impaired spatial memory. Female mammals are considered the “neutral” sex; additional physiological steps are required for male differentiation, and more steps bring more possibilities for errors in differentiation. Some examples of male anomalous sexual differentiation include 5α-reductase deficiency (in which XY individuals are born with ambiguous genitalia because of a lack of dihydrotestosterone and are reared as females, but masculinization occurs during puberty) and androgen insensitivity syndrome or TFM (in which XY individuals lack receptors for androgens and develop as females). By studying individuals who do not neatly fall into the dichotic boxes of female or male and for whom the process of sexual differentiation is atypical, behavioral endocrinologists glean hints about the process of typical sexual differentiation. We may ultimately want to know how hormones mediate sex differences in the human brain and behavior (to the extent to which these differences occur).

To understand the mechanisms underlying sex differences in the brain and behavior, we return to the birdsong example. Birds provide the best evidence that behavioral sex differences are the result of hormonally induced structural changes in the brain ( Goodson, Saldanha, Hahn, & Soma, 2005 ). In contrast to mammals, in which structural differences in neural tissues have not been directly linked to behavior, structural differences in avian brains have been directly linked to a sexually behavior: birdsong. Several brain regions in songbirds display significant sex differences in size. Two major brain circuit pathways, (1) the song production motor pathway and (2) the auditory transmission pathway, have been implicated in the learning and production of birdsong. Some parts of the song production pathway of male zebra finches are 3 to 6 times larger than those of female conspecifics. The larger size of these brain areas reflects that neurons in these nuclei are larger, more numerous, and farther apart. Although castration of adult male birds reduces singing, it does not reduce the size of the brain nuclei controlling song production.

Similarly, androgen treatment of adult female zebra finches does not induce changes either in singing or in the size of the song control regions. Thus, activational effects of steroid hormones do not account for the sex differences in singing behavior or brain nucleus size in zebra finches. The sex differences in these structures are organized or programmed in the egg by estradiol (masculinizes) or the lack of steroids (feminizes). Taken together, estrogens appear to be necessary to activate the neural machinery underlying the song system in birds. The testes of birds primarily produce androgens, which enter the circulation. The androgens enter neurons containing aromatase , which converts them to estrogens. Indeed, the brain is the primary source of estrogens, which activate masculine behaviors in many bird species. Figure 2: The sexually dimorphic nuclei of the preoptic area (SDN-POA) Gonadal steroid hormones have organizing effects upon brain and behavior. The organizing effects of steroid hormones are relatively constrained to the early stages of development. Exposure to testosterone (which is converted to estradiol) or estradiol causes masculinization of the brain.

These are cross-sections through the brains of rats that show a male (left), a female (center), and a female treated with testosterone as a newborn (right). Note that the SDN-POA (the dark cell bodies) of the male are substantially larger than those of the untreated female but are equal in size to those of the testosterone-treated female. The extent that these sex differences in brain structure account for sex differences in behavior remain unspecified in mammals. OC = optic chiasm; SCN = suprachiasmatic nucleus; V = third ventricle. Sex differences in human brain size have been reported for years. More recently, sex differences in specific brain structures have been discovered (Figure 2). Sex differences in a number of cognitive functions have also been reported. Females are generally more sensitive to auditory information, whereas males are more sensitive to visual information. Females are also typically more sensitive than males to taste and olfactory input. Women display less lateralization of cognitive functions than men. On average, females generally excel in verbal, perceptual, and fine motor skills, whereas males outperform females on quantitative and visuospatial tasks, including map reading and direction finding. Although reliable sex differences can be documented, these differences in ability are slight.

It is important to note that there is more variation within each sex than between the sexes for most cognitive abilities (Figure 3). Figure 3: The average sex differences in human performance often reflect significant overlap between the sexes There are often greater differences in performance between individuals of the same sex (for example, between Steve and Rick in the figure) than between individuals of the opposite sex (for example, between Steve and Jane in the figure). Aggressive Behaviors The possibility for aggressive behavior exists whenever the interests of two or more individuals are in conflict ( Nelson, 2006 ). Conflicts are most likely to arise over limited resources such as territories, food, and mates. A social interaction decides which animal gains access to the contested resource. In many cases, a submissive posture or gesture on the part of one animal avoids the necessity of actual combat over a resource. Animals may also participate in threat displays or ritualized combat in which dominance is determined but no physical damage is inflicted. There is overwhelming circumstantial evidence that androgenic steroid hormones mediate aggressive behavior across many species. First, seasonal variations in blood plasma concentrations of testosterone and seasonal variations in aggression coincide.

For instance, the incidence of aggressive behavior peaks for male deer in autumn, when they are secreting high levels of testosterone. Second, aggressive behaviors increase at the time of puberty, when the testes become active and blood concentrations of androgens rise. Juvenile deer do not participate in the fighting during the mating season. Third, in any given species, males are generally more aggressive than females. This is certainly true of deer; relative to stags, female deer rarely display aggressive behavior, and their rare aggressive acts are qualitatively different from the aggressive behavior of aggressive males. Finally, castration typically reduces aggression in males, and testosterone replacement therapy restores aggression to pre-castration levels. There are some interesting exceptions to these general observations that are outside the scope of this module. As mentioned, males are generally more aggressive than females. Certainly, human males are much more aggressive than females. Many more men than women are convicted of violent crimes in North America. The sex differences in human aggressiveness appear very early. At every age throughout the school years, many more boys than girls initiate physical assaults. Almost everyone will acknowledge the existence of this sex difference, but assigning a cause to behavioral sex differences in humans always elicits much debate.

It is possible that boys are more aggressive than girls because androgens promote aggressive behavior and boys have higher blood concentrations of androgens than girls. It is possible that boys and girls differ in their aggressiveness because the brains of boys are exposed to androgens prenatally and the “wiring” of their brains is thus organized in a way that facilitates the expression of aggression. It is also possible that boys are encouraged and girls are discouraged by family, peers, or others from acting in an aggressive manner. These three hypotheses are not mutually exclusive, but it is extremely difficult to discriminate among them to account for sex differences in human aggressiveness. Researchers have electrically stimulated particular regions in people’s brains, and these individuals have burst into aggressive, violent behavior, helping demonstrate that such responses are hardwired into us. [Image: Riccardo Cuppini] What kinds of studies would be necessary to assess these hypotheses? It is usually difficult to separate out the influences of environment and physiology on the development of behavior in humans. For example, boys and girls differ in their rough-and-tumble play at a very young age, which suggests an early physiological influence on aggression.

However, parents interact with their male and female offspring differently; they usually play more roughly with male infants than with females, which suggests that the sex difference in aggressiveness is partially learned. This difference in parental interaction style is evident by the first week of life. Because of these complexities in the factors influencing human behavior, the study of hormonal effects on sex-differentiated behavior has been pursued in nonhuman animals, for which environmental influences can be held relatively constant. Animal models for which sexual differentiation occurs postnatally are often used so that this process can be easily manipulated experimentally. Again, with the appropriate animal model, we can address the questions posed above: Is the sex difference in aggression due to higher adult blood concentrations of androgens in males than in females, or are males more aggressive than females because their brains are organized differently by perinatal hormones? Are males usually more aggressive than females because of an interaction of early and current blood androgen concentrations? If male mice are castrated prior to their sixth day of life, then treated with testosterone propionate in adulthood, they show low levels of aggression. Similarly, females ovariectomized prior to their sixth day but given androgens in adulthood do not express male-like levels of aggression.

Treatment of perinatally gonadectomized males or females with testosterone prior to their sixth day life and also in adulthood results in a level of aggression similar to that observed in typical male mice. Thus, in mice, the proclivity for males to act more aggressively than females is organized perinatally by androgens but also requires the presence of androgens after puberty in order to be fully expressed. In other words, aggression in male mice is both organized and activated by androgens. Testosterone exposure in adulthood without prior organization of the brain by steroid hormones does not evoke typical male levels of aggression. The hormonal control of aggressive behavior in house mice is thus similar to the hormonal mediation of heterosexual male mating behavior in other rodent species. Aggressive behavior is both organized and activated by androgens in many species, including rats, hamsters, voles, dogs, and possibly some primate species. Parental Behaviors Parental behavior can be considered to be any behavior that contributes directly to the survival of fertilized eggs or offspring that have left the body of the female. There are many patterns of mammalian parental care. The developmental status of the newborn is an important factor driving the type and quality of parental care in a species.

Maternal care is much more common than paternal care. The vast majority of research on the hormonal correlates of mammalian parental behavior has been conducted on rats. Rats bear altricial young, and mothers perform a cluster of stereotyped maternal behaviors, including nest building, crouching over the pups to allow nursing and to provide warmth, pup retrieval, and increased aggression directed at intruders. If you expose nonpregnant female rats (or males) to pups, their most common reaction is to huddle far away from them. Rats avoid new things (neophobia). However, if you expose adult rats to pups every day, they soon begin to behave maternally. This process is called concaveation or sensitization and it appears to serve to reduce the adult rats’ fear of pups. Of course a new mother needs to act maternal as soon as her offspring arrive—not in a week. The onset of maternal behavior in rats is mediated by hormones. Several methods of study, such as hormone removal and replacement therapy, have been used to determine the hormonal correlates of rat maternal behavior.

A fast decline of blood concentrations of progesterone in late pregnancy after sustained high concentrations of this hormone, in combination with high concentrations of estradiol and probably prolactin and oxytocin, induces female rats to behave maternally almost immediately in the presence of pups. This pattern of hormones at parturition overrides the usual fear response of adult rats toward pups, and it permits the onset of maternal behavior. Thus, the so-called maternal “instinct” requires hormones to increase the approach tendency and lower the avoidance tendency. Laboratory strains of mice and rats are usually docile, but mothers can be quite aggressive toward animals that venture too close to their litter. Progesterone appears to be the primary hormone that induces this maternal aggression in rodents, but species differences exist. The role of maternal aggression in women’s behavior has not been adequately described or tested. Although cortisol may not directly increase maternal behaviors, the next time your mom makes that extra effort for you, you know one hormone to thank.

[Image: dcnerd, CC BY-NC-ND 2.0, A series of elegant experiments by Alison Fleming and her collaborators studied the endocrine correlates of the behavior of human mothers as well as the endocrine correlates of maternal attitudes as expressed in self-report questionnaires. Responses such as patting, cuddling, or kissing the baby were called affectionate behaviors; talking, singing, or cooing to the baby were considered vocal behaviors. Both affectionate and vocal behaviors were considered approach behaviors. Basic caregiving activities, such as changing diapers and burping the infants, were also recorded. In these studies, no relationship between hormone concentrations and maternal responsiveness, as measured by attitude questionnaires, was found. For example, most women showed an increasing positive self-image during early pregnancy that dipped during the second half of pregnancy, but recovered after parturition. A related dip in feelings of maternal engagement occurred during late pregnancy, but rebounded substantially after birth in most women. However, when behavior, rather than questionnaire responses, was compared with hormone concentrations, a different story emerged. Blood plasma concentrations of cortisol were positively associated with approach behaviors.

In other words, women who had high concentrations of blood cortisol, in samples obtained immediately before or after nursing, engaged in more physically affectionate behaviors and talked more often to their babies than mothers with low cortisol concentrations. Additional analyses from this study revealed that the correlation was even greater for mothers that had reported positive maternal regard (feelings and attitudes) during gestation. Indeed, nearly half of the variation in maternal behavior among women could be accounted for by cortisol concentrations and positive maternal attitudes during pregnancy. Presumably, cortisol does not induce maternal behaviors directly, but it may act indirectly on the quality of maternal care by evoking an increase in the mother’s general level of arousal, thus increasing her responsiveness to infant-generated cues. New mothers with high cortisol concentrations were also more attracted to their infant’s odors, were superior in identifying their infants, and generally found cues from infants highly appealing ( Fleming, Steiner, & Corter, 1997 ). The medial preoptic area is critical for the expression of rat maternal behavior. The amygdala appears to tonically inhibit the expression of maternal behavior. Adult rats are fearful of pups, a response that is apparently mediated by chemosensory information.

Lesions of the amygdala or afferent sensory pathways from the vomeronasal organ to the amygdala disinhibit the expression of maternal behavior. Hormones or sensitization likely act to disinhibit the amygdala, thus permitting the occurrence of maternal behavior. Although correlations have been established, direct evidence of brain structural changes in human mothers remains unspecified ( Fleming & Gonzalez, 2009 ). Considered together, there are many examples of hormones influencing behavior and of behavior feeding back to influence hormone secretion. More and more examples of hormone–behavior interactions are discovered, including hormones in the mediation of food and fluid intake, social interactions, salt balance, learning and memory, stress coping, as well as psychopathology including depression, anxiety disorders, eating disorders, postpartum depression, and seasonal depression. Additional research should reveal how these hormone–behavior interactions are mediated. Outside Resources Discussion Questions What are some of the problems associated with attempting to determine causation in a hormone–behavior interaction? What are the best ways to address these problems? Hormones cause changes in the rates of cellular processes or in cellular morphology. What are some ways that these hormonally induced cellular changes might theoretically produce profound changes in behavior?

List and describe some behavioral sex differences that you have noticed between boys and girls. What causes girls and boys to choose different toys? Do you think that the sex differences you have noted arise from biological causes or are learned? How would you go about establishing your opinions as fact? Why is it inappropriate to refer to androgens as “male” hormones and estrogens as “female” hormones? Imagine that you discovered that the brains of architects were different from those of non-architects—specifically, that the “drawstraightem nuclei” of the right temporal lobe were enlarged in architects as compared with non-architects. Would you argue that architects were destined to be architects because of their brain organization or that experience as an architect changed their brains? How would you resolve this issue? Vocabulary The primary androgen secreted by the testes of most vertebrate animals, including men. References Alexander, G. M. & Hines, M. (2002). Sex differences in response to children’s toys in nonhuman primates (Cercopithecus aethiops sabaeus). Evolution and Human Behavior, 23, 467–479. Berenbaum, S.

A., Martin, C. L., Hanish, L. D., Briggs, P. T., & Fabes, R. A. (2008). Sex differences in children’s play. In J. B. Becker, K. J. Berkley, N. Geary, E. Hampson, J. Herman, & E. Young (Eds.), Sex differences in the brain: From genes to behavior. New York: Oxford University Press. Dabbs, J. M. (2000). Heroes, rogues, and lovers: Testosterone and behavior. Columbus, OH: McGraw Hill. Fleming, A. S., & Gonzalez, A. (2009). Neurobiology of human maternal care. In P. T. Ellison & P. B. Gray (Eds.), Endocrinology of social relationships (pp. 294–318). Cambridge, MA: Harvard University Press. Fleming, A. S., Steiner, M., & Corter, C. (1997). Cortisol, hedonics, and maternal responsiveness in human mothers.

Hormones and Behavior, 32, 85–98. Goodson, J. L., Saldanha, C. J., Hahn, T. P., Soma, K. K. (2005). Recent advances in behavioral neuroendocrinology: Insights from studies on birds. Hormones and Behavior, 48, 461–73. Kidd, K. A., Blanchfield, P. J., Mills, K. H., Palace, V. P., Evans, R. E. Lazorchak, J. M. & Flick, R. (2007). Collapse of a fish population following exposure to a synthetic estrogen. Proceedings of the National Academy of Sciences,104, 8897–8901. Nelson, R. J. (Ed.) (2006). Biology of aggression. New York: Oxford University Press. Nelson, R.J. (2011). An introduction to behavioral endocrinology (4th ed.). Sunderland, MA: Sinauer Associates. Phoenix, C. H., Goy, R. W., Gerall, A.

A., & Young, W. C. (1959). Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig. Endocrinology, 65: 369–382. van Anders, S., Hamilton, L., Schmidt, N., & Watson, N. (2007). Associations between testosterone secretion and sexual activity in women. Hormones and Behavior, 51, 477–82. Authors Randy J. Nelson Randy J. Nelson has two PhDs (Psychology and Endocrinology) and is Professor and Chair of Neuroscience and Professor of Psychology at The Ohio State University. He has been appointed as University Distinguished Professor for his work on hormones, biological rhythms, and behavior. Dr. Nelson has published nearly 400 papers and several books on these topics. Creative Commons License Irritable Male Syndrome Irritable Male Syndrome Top Concentration Killers Slideshow WebMD Live Events Transcript Stressed out? Grumpy? Moody?

If you're a guy and these words describe your mental state, you may be suffering from what psychotherapist Jed Diamond calls "irritable male syndrome" in his book of the same name. Yes, ladies, even men can fall victim to hormone fluctuations. We discussed IMS and its effects on men when Diamond joined us on Nov. 10, 2004. The opinions expressed herein are the guests' alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only. MODERATOR: Welcome to WebMD Live, Jed. Thank you for joining us today. What is irritable male syndrome? Is this a new problem or a newly recognized problem? DIAMOND: This is really based on 40 years of my own clinical research as well as responses from 10,000 men. We've discovered why millions of men are becoming angry and depressed, and why they so often vent their frustration on the women they love the most.

Irritable male syndrome (IMS) can be defined as a state of hypersensitivity, frustration, anxiety , and anger that occurs in males and is associated with biochemical changes, hormonal fluctuations, stress , and loss of male identity. MODERATOR: How are depression and aggression linked in men? DIAMOND: What we've found was that most of the professional research and, in some ways, common experience have assumed women suffered from depression at twice the rate as males. We've found in our research that men often experience depression in different ways than women. And often, irritability and anger and hypersensitivity are male aspects of depression that often go unrecognized. MODERATOR: What is the role of stress in IMS? DIAMOND: What we found is that stress is destroying marriages and destroying relationships. There are a number of reasons for this. There are more new and more deadly stresses that we face today than ever before. In the past, stress came from physical sources. A wild animal would run into the camp or there would be physical danger. And men knew how to respond to that, the fight or flight response. But now, stress comes from many other sources.

From too much traffic, stress from where our country is going, and the direction we're going, fears about unknown attacks from outside or stresses from inside our country. The traditional male responses don't work. We can't fight it if we don't know what it is. As a result, male stress tends to be taken out on the partners that we are in relationship with. MODERATOR: Some men turn inward and harm themselves; others become aggressive. What determines which way a man will go? DIAMOND: As I described IMS as having two types or directions, we can say it's either acted in -- reflecting in depression, and if not treated even suicide . Or it's acted out in terms of anger, aggression and violence. What determines which one has to do with often our upbringing, in some cases our genetic heritage and biochemistry. But quite often, we see men going from one extreme to the other. These are the men that seem to hold it inside and then, out of the blue, tend to explode. MODERATOR: Are there hormonal factors in IMS? We so easily throw around the idea that hormones affect women's moods, but for men it never seems to come up.

DIAMOND: Again, there is the assumption that women are hormonal but men are moved more by logic. But the truth is men are as hormonally driven as women. In fact, men have a number of hormonal cycles: 1) Men's testosterone, for instance, varies and goes up and down four or five times an hour. 2) There are daily cycles with testosterone being higher in the morning and lower at night. 3) Men have a monthly hormonal cycle that is unique to each man, but men can actually track their moods and recognize they are related to hormonal changes through the month. 4) We know that there are seasonal cycles with testosterone higher in November and lower in April. 5) We know about hormonal cycles with males during adolescence, but also the years between 40 and 55 have what we call male menopause or andropause. 6) Finally, we know there are hormonal changes in men going through IMS, related to stress in a man's life. "What we've found is that one of the primary symptoms is denial. That is, men think the problem is anywhere other than in themselves." MEMBER QUESTION: What causes hormones to go out of whack in a man?

DIAMOND: There are a lot of things that can make hormones go out of whack. Let's start with something we all do, and that is eating food. If we gain weight, we run the potential of increasing IMS. Here is how it works: In the body, a certain amount of testosterone gets converted to estrogen. Males and females have estrogen and testosterone in our bodies. When we put on weight, our fat cells are more active in converting testosterone into estrogen. The more estrogen we have and the less testosterone we have, the more irritable we become and the less sense of our own manly strength that we have. That's one way they get out of whack. A second way is that we know when we are under a great deal of stress our testosterone levels drop. The third way they get out of whack is when we use various medications that can have in impact on hormonal levels. Many people are using multiple medications, not always with the knowledge of their doctors. And when I say medication, I include herbal remedies that many people think that because they're natural, they're safe, or that they're not real medications.

What I tell people is that all of these things are important to be explored by your health care provider to be sure you're not causing reactions between the various things you may be taking that can make your condition worse rather than better. MEMBER QUESTION: What are the signs of irritable male syndrome? My husband is depressed and stressed. Sometimes I have no idea what sets him off. How is IMS different from just regular depression? DIAMOND: We've set up a specific web site for you, at On that site, you can take a quiz that will score your answers and give you an idea of whether you are suffering from IMS or the man that you may be concerned about is suffering. The quiz will also tell you which of nine types of IMS a man may have. What we've found is that one of the primary symptoms is denial. That is, men think the problem is anywhere other than in themselves. They think it's their wives, their boss, people on the highway, the people in the White House, anybody but what's going on with themselves. So one of the primary things we help couples do is help men break through the denial.

What we know is that depression obviously can be present in people, male or female, who are not experiencing IMS. But we do think depression is a very significant aspect of IMS, and it is often unrecognized in males, because we tend to see irritability and anger and aggression as something that is acted-out behavior or negative behavior. We rarely see how sad and unhappy the men are. Testosterone Testosterone Test Overview A testosterone test checks the level of this male hormone (androgen) in the blood . Testosterone affects sexual features and development. In men, it is made in large amounts by the testicles . In both men and women, testosterone is made in small amounts by the adrenal glands , and in women, by the ovaries . The pituitary gland controls the level of testosterone in the body. When the testosterone level is low, the pituitary gland releases a hormone called luteinizing hormone (LH) . This hormone tells the testicles to make more testosterone. Before puberty , the testosterone level in boys is normally low. Testosterone increases during puberty. This causes boys to develop a deeper voice, get bigger muscles, make sperm , and get facial and body hair .

The level of testosterone is the highest around age 40, then gradually becomes less in older men. In women, the ovaries account for half of the testosterone in the body. Women have a much smaller amount of testosterone in their bodies compared to men. But testosterone plays an important role throughout the body in both men and women. It affects the brain , bone and muscle mass, fat distribution, the vascular system, energy levels, genital tissues, and sexual functioning. Most of the testosterone in the blood is bound to a protein called sex hormone binding globulin (SHBG). Testosterone that is not bound ("free" testosterone) may be checked if a man or a woman is having sexual problems. Free testosterone also may be tested for a person who has a condition that can change SHBG levels, such as hyperthyroidism or some types of kidney diseases. Total testosterone levels vary throughout the day. They are usually highest in the morning and lowest in the evening. Why It Is Done A testosterone test is done to: See why a man is having problems in fathering a child ( infertility ). A low amount of testosterone can lead to low sperm counts. Check a man's sexual problems.

Having a low level of testosterone may lower a man's sex drive or not allow him to have an erection ( erectile dysfunction ). See whether a high level of testosterone is causing a boy younger than age 10 to have early signs of puberty. Find out why a woman is developing male features, such as excessive facial and body hair ( hirsutism ) and a deep voice. Find out why a woman is having irregular menstrual periods. See if testosterone-lowering medicines are working in a man with advanced prostate cancer . Find the cause of osteoporosis in a man. Continued How To Prepare You do not need to do anything before you have this test. Your doctor may want you to do a morning blood test because testosterone levels are highest between 7 a.m. and 9 a.m. How It Is Done The health professional taking a sample of blood will: Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein. Clean the needle site with alcohol. Put the needle into the vein. More than one needle stick may be needed. Attach a tube to the needle to fill it with blood.

Remove the band from your arm when enough blood is collected. Put a gauze pad or cotton ball over the needle site as the needle is removed. Put pressure to the site and then a bandage. How It Feels The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch. Risks There is very little chance of a problem from having a blood sample taken from a vein. You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes. In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis . A warm compress can be used several times a day to treat this. Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin , warfarin ( Coumadin ), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken. Results

Question: What is the name of the hormone which is said to give males their aggressiveness?
Answer: TESTOSTERONE