LUST, ROMANCE, ATTACHMENT: DO THE SIDE EFFECTS OF SEROTONIN-ENHANCING ANTIDEPRESSANTS JEOPARDIZE ROMANTIC LOVE, MARRIAGE AND FERTILITY?

Today millions of people take serotonin-enhancing antidepressants. These medications cause emotional blunting and dysfunction in sexual desire, arousal and orgasm in both men and women. We propose that these antidepressants have other side effects, due to their impact on several related neural mechanisms. Homo sapiens has evolved three distinct brain systems for courtship, reproduction and parenting. The sex drive evolved to motivate men and women to initiate sexual contact with a range of partners; romantic love evolved to motivate them to focus their courtship energy on specific individuals, thereby conserving mating time and energy; partner attachment evolved to motivate our forebears to maintain a stable mateship long enough to rear a child through infancy together. Studies using functional Magnetic Resonance Imaging (fMRI) indicate that romantic love is associated with dopaminergic pathways in the brain’s reward system, pathways that are suppressed by elevated central serotonin. Hence we hypothesize that serotonin-enhancing antidepressants can jeopardize one’s ability to fall in love. Due to their impact on the sex drive, these medications can also jeopardize other brain/body mechanisms that enhance mate assessment, mate choice, pair formation and partner attachment. This paper discusses the biological relationships between the sex drive, romantic love and attachment, as well as other evolved reproductive mechanisms, to illustrate how serotonin-enhancing antidepressants can jeopardize feelings of romance, attachment and fertility. LUST, ROMANCE, ATTACHMENT: DO THE SIDE EFFECTS OF SEROTONINENHANCING ANTIDEPRESSANTS JEOPARDIZE ROMANTIC LOVE, MARRIAGE AND FERTILITY? Helen Fisher and J. Anderson Thomson, Jr. Helen Fisher, Anthropologist Dept. Anthropology, Rutgers University J. Anderson Thomson, psychiatrist Counseling and Psychological Services, Department of Student Health, University of Virginia Corresponding Author: Helen E. Fisher Office: 4 East 70th Street New York City, NY 10021 Today millions of people of reproductive age take selective serotonin-reuptake inhibitors (SSRIs) and other serotonin enhancing antidepressants. Approximately 80% of these drugs are prescribed by non-psychiatric physicians, including internists, general practitioners, pediatricians and gynecologists who disseminate them to a wide array of men and women. In the first five months of 2004, American doctors wrote 46 million prescriptions for antidepressants, largely for these drugs (Morais 2004). In the United States alone, antidepressants account for $14 billion a year in wholesale revenues (Morais 2004). These medications effectively treat a wide range of serious conditions, including major depression, post traumatic stress disorder, generalized anxiety disorders, panic disorders, obsessive compulsive disorder, social phobias, eating disorders, Asperger's syndrome, irritable bowel syndrome and chronic pain syndromes. But they also produce various side-effects. It is well established that in both men and women these antidepressants can cause emotional blunting, weight gain and several types of sexual dysfunction, interfering with sexual desire, sexual arousal, genital sensation, lubrication, erection, ejaculation and orgasm (Rosen et al 1999; Montejo et al 2001). The number of men and women affected by these forms of sexual dysfunction vary; some studies report that as many as 73% of patients taking serotoninenhancing antidepressants suffer one or more of these sexual side effects (Montejo et al 2001). We propose that serotonin-enhancing antidepressants can have far more serious psychological, social and genetic consequences, however, due to their effects on several other neural mechanisms that evolved to enable mate assessment, mate choice, mate pursuit, feelings of romantic love and expressions of attachment to a long term partner. This paper discusses the neural correlates of the three primary brain systems for courtship, mating, pair formation and reproduction: 1) the sex drive; 2) romantic love; and 3) male/female attachment (companionate love). It explores the neurochemical relationships between these three neural systems to show how serotonin-enhancing antidepressants can potentially jeopardize the ability to fall in love and maintain a stable, long-term partnership. It discusses the potential effects of long-term useof serotonin-enhancing medications on other brain/body mechanisms that evolved to foster courtship and pairbond stability, including penile erection and female orgasm. Last, it illustrates how serotonin-enhancing antidepressants can adversely affect fertility and one’s genetic future. Three neural systems for mating and reproduction Neuroscientists currently believe that the basic human emotions and motivations arise from distinct systems of neural activity; that these brain systems derive from mammalian precursors; and that these brain mechanisms evolved to enable survival and reproduction (Davidson 1994; Panksepp 1998). Among these primary neural systems are three discrete, interrelated motivation/emotion systems for mating, reproduction and parenting: the sex drive, romantic love and male/female attachment. Each of these motivation/emotion systems is associated with a different behavioral repertoire; each is associated with a different and dynamic constellation of neural correlates; and each evolved to direct a different aspect of reproduction (Fisher 1998). The sex drive is characterized by the craving for sexual gratification. It is associated primarily with the estrogens and androgens in non-primate mammalian species. In humans and other higher primates the estrogens have little direct influence on sexual desire (Meston and Frolich 2000); instead the androgens, particularly testosterone, is crucial to sexual desire in both sexes (Edwards and Booth 1994; Sherman 1994; Van Goozen et al 1997). The sex drive evolved principally to motivate individuals to seek sexual union with a range of reproductive partners. Romantic love (also known as obsessive love, passionate love or being in love) is characterized by intense energy, focused courtship attention, ecstasy, mood swings, sexual possessiveness, emotional dependency, obsessive thinking about the beloved, craving for emotional union with the beloved and intense motivation to win this preferred mating partner (Fisher 1998; Gonzaga et al. 2001; Harris 1995; Hatfield et al. 1988; Hatfield and Sprecher 1986; Shaver et al. 1987; Tennov 1979). Evidence suggests that romantic love is primarily associated with elevated activity in dopaminergic pathways of the reward system of the brain (Aron et al,2005; Bartels and Zeki 2000; Bartels and Zeki 2004); and data suggest that other mammals share central biological and behavioral aspects of this brain system (Gingrich et al., 2000; Wang et al., 1999; Liu and Wang 2003; Fabre-Nys et al 1997). The neural system associated with romantic love evolved to motivate individuals to prefer a specific mating partner, thereby conserving courtship time and energy. Partner attachment in humans is associated with feelings of calm, security, social comfort and emotional union with a long-term mating partner, as well as with some of the traits of mammalian attachment, including mutual territory defense and/or nest/home building, mutual feeding and grooming, maintenance of close proximity, separation anxiety, shared parental chores and affiliative gestures (Carter et al., 1997, Young, Wang, & Insel, 1998; Lim, Murphy, & Young, 2004; Lim and Young 2004). Animal studies suggest that this brain system is associated primarily with the neuropeptides, oxytocin and vasopressin (Carter 1992; Winslow et al 1993; Lim, Murphy & Young 2004; Lim and Young 2004). Adult male/female partner attachment evolved primarily to motivate individuals to sustain an affiliative connection with a reproductive partner at least long enough to complete species-specific parental duties (Fisher 1992). We propose that when patients use serotonin-enhancing antidepressants, they can potentially jeopardize not only their sex drive but also these related neural mechanisms for romantic love and partner attachment. The Sex Drive The androgens, particularly testosterone, is central to sexual desire in both men and women (Edwards and Booth 1994; Sherman 1994; Van Goozen et al 1997). Individuals who have higher circulating levels of testosterone tend to engage in more sexual activity (Edwards and Booth 1994; Sherwin 1994). Male athletes who use testosterone and other anabolic steroids to elevate strength and stamina have more sexual thoughts, more morning erections, more sexual encounters and more orgasms. Middle-aged women who inject or apply testosterone cream to the skin boost sexual desire. The male libido peaks in the early twenties, when the activity of testosterone is highest. Many women feel more sexual desire around ovulation, when testosterone increases (Van Goozen et al 1997). Both sexes also have fewer sexual fantasies, masturbate less regularly and engage in less intercourse as they age, as testosterone declines (Edwards and Booth 1994). People vary in their degree and frequency of sexual desire, in part because levels of testosterone are inherited (Meikle et al 1988). Moreover, the balance between testosterone, estrogen and other bodily systems, as well as social circumstances, childhood experiences and a host of other factors play a role in when, where and how often one feels lust (Nyborg 1994). Nevertheless, testosterone is central to the sex drive. The sex drive is also associated with a specific range of neural correlates. Using functional Magnetic Resonance Imaging (fMRI), Arnow and colleagues report that when young male heterosexual subjects look at erotic video material while wearing a custom-built pneumatic pressure cuff around the penis, they show strong activations in the right subinsular region, including the claustrum, the left caudate and putamen, the rig