Addiction

# Overview
Addiction was a term used to describe a devotion, attachment, dedication, inclination, etc. Nowadays, however, the term addiction is used to describe a recurring compulsion by an individual to engage in some specific activity, despite harmful consequences to the individual's health, mental state or social life. The term is often reserved for drug addictions but it is sometimes applied to other compulsions, such as problem gambling, and compulsive overeating. Factors that have been suggested as causes of addiction include genetic, biological/pharmacological and social factors.

# Terminology and usage
Decades ago addiction was a pharmacological term that clearly referred to the use of a tolerance-inducing drug in sufficient quantity as to cause tolerance (the requirement that greater dosages of a given drug be used to produce an identical effect as time passes). With that definition, humans (and indeed all mammals) can become addicted to various drugs quickly. Almost at the same time, a lay definition of addiction developed. This definition referred to individuals who continued to use a given drug despite their own best interest. This latter definition is now thought of as a disease state by the medical community.
Physical dependence, abuse of, and withdrawal from drugs and other miscellaneous substances is outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR). Terminology has become quite complicated in the field. To wit, pharmacologists continue to speak of addiction from a physiologic standpoint (some call this a physical dependence); psychiatrists refer to the disease state as dependence; most other physicians refer to the disease as addiction. The field of psychiatry is now considering, as they move from DSM-IV to DSM-V, transitioning from "dependence" to "addiction" as terminology for the disease state.
The medical community now makes a careful theoretical distinction between physical dependence (characterized by symptoms of withdrawal) and psychological dependence (or simply addiction). Addiction is now narrowly defined as "uncontrolled, compulsive use"; if there is no harm being suffered by, or damage done to, the patient or another party, then clinically it may be considered compulsive, but to the definition of some it is not categorized as "addiction". In practice, the two kinds of addiction are not always easy to distinguish. Addictions often have both physical and psychological components.
There is also a lesser known situation called pseudo-addiction.(Weissman and Haddox, 1989) A patient will exhibit drug-seeking behavior reminiscent of psychological addiction, but they tend to have genuine pain or other symptoms that have been undertreated.  Unlike true psychological addiction, these behaviors tend to stop when the pain is adequately treated.
The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal.  While opiates are essential in the treatment of acute pain, the benefit of this class of medication in chronic pain is not well proven.  Clearly, there are those who would not function well without opiate treatment; on the other hand, many states are noting significant increases in non-intentional deaths related to opiate use. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.
Not all doctors agree on what addiction or dependency is. Traditionally, addiction has been defined as being possible only to a psychoactive substance (for example alcohol,  tobacco and other drugs) which ingested cross the blood-brain barrier, altering the natural chemical behavior of the brain temporarily.  However, "Studies on phenomenology, family history, and response to treatment suggest that intermittent explosive disorder, kleptomania, pathological gambling, pyromania, and trichotillomania may be related to mood disorders, alcohol and psychoactive substance abuse, and anxiety disorders (especially obsessive-compulsive disorder).
It is generally accepted that addiction is a disease, a state of physiological or psychological dependence or devotion to something manifesting as a condition in which medically significant symptoms liable to have a damaging effect are present.
Many people, both psychology professionals and laypersons, now feel that there should be accommodation made to include psychological dependency on such things as gambling, food, sex, pornography, computers, work, exercise, cutting, shopping, and religion so these behaviours count as diseases as well and don't cause guilt, shame, fear, hopelessness, failure, rejection,anxiety, or humiliation symptoms associated with, among other medical conditions, depression,epilepsy,  and hyperreligiosity  In depression related to religious addiction "The religious addict seeks to avoid pain and overcome shame by becoming involved in a belief system which offers security through its rigidity and its absolute values." While religion and spirituality may play a key role in psychotherapeutic support and recovery, it can also be a source of pain, guilt and exclusion, and religious themes may also play a negative role in psychopathology.  Although, the above mentioned are things or tasks which, when used or performed, do not fit into the traditional view of addiction and may be better defined as an obsessive-compulsive disorder,withdrawal symptoms may occur with abatement of such behaviors.  It is said by those who adhere to a traditionalist view that these withdrawal-like symptoms are not strictly reflective of an addiction, but rather of a behavioral disorder.  However, understanding of neural science, the brain, the nervous system, human behavior, and affective disorders has revealed "the impact of molecular biology in the mechanisms underlying developmental processes and in the pathogenesis of disease".  The use of thyroid hormones as an effective adjunct treatment for affective disorders has been studied over the past three decades and has been confirmed repeatedly.  In spite of traditionalist protests and warnings that overextension of definitions may cause the wrong treatment to be used (thus failing the person with the behavioral problem), popular media, and some members of the field, do represent the aforementioned behavioral examples as addictions.
Recently, some have modeled addiction using the tools of Economics, for instance, by calculating the elasticity of addictive goods and determining to what extent present income and consumption has on future consumption. 

# Varied forms of addiction

## Physical dependency
Physical dependence on a substance is defined by the appearance of characteristic withdrawal symptoms when the substance is suddenly discontinued. Opiates, benzodiazepines, barbiturates, alcohol and nicotine induce physical dependence. On the other hand, some categories of substances share this property and are still not considered addictive: cortisone, beta-blockers and most antidepressants are examples. So, while physical dependency can be a major factor in the psychology of addiction and most often becomes a primary motivator in the continuation of an addiction, the initial primary attribution of an addictive substance is usually its ability to induce pleasure, although with continued use the goal is not so much to induce pleasure as it is to relieve the anxiety caused by the absence of a given addictive substance, causing it to become used compulsively. An example of this is nicotine; A cigarette can be described as pleasurable, but is in fact fulfilling the physical addiction of the user, and therefore, is achieving pleasurable feelings relative to his/her previous state of physical withdrawal. Further, the physical dependency of the nicotine addict on the substance itself becomes an overwhelming factor in the continuation of use.
Some substances induce physical dependence or physiological tolerance - but not addiction - for example many laxatives, which are not psychoactive; nasal decongestants, which can cause rebound congestion if used for more than a few days in a row; and some antidepressants, most notably venlafaxine, paroxetine and sertraline, as they have quite short half-lives, so stopping them abruptly causes a more rapid change in the neurotransmitter balance in the brain than many other antidepressants.  Many non-addictive prescription drugs should not be suddenly stopped, so a doctor should be consulted before abruptly discontinuing them.
The speed with which a given individual becomes addicted to various substances varies with the substance, the frequency of use, the means of ingestion, the intensity of pleasure or euphoria, and the individual's genetic and psychological susceptibility. Some people may exhibit alcoholic tendencies from the moment of first intoxication, while most people can drink socially without ever becoming addicted. Opioid dependent individuals have different responses to even low doses of opioids than the majority of people, although this may be due to a variety of other factors, as opioid use heavily stimulates pleasure-inducing neurotransmitters in the brain. Nonetheless, because of these variations, in addition to the adoption and twin studies that have been well replicated, much of the medical community is satisfied that addiction is in part genetically moderated. That is, one's genetic makeup may regulate how susceptible one is to a substance and how easily one may become psychologically attached to a pleasurable routine.
Eating disorders are complicated pathological mental illnesses and thus are not the same as addictions described in this article. Eating disorders, which some argue are not addictions at all, are driven by a multitude of factors, most of which are highly different than the factors behind addictions described in this article.

## Psychological dependency
Psychological dependency is a dependency of the mind, and leads to psychological withdrawal symptoms (such as cravings, irritability, insomnia, depression, anorexia etc). Addiction can in theory be derived from any rewarding behavior, and is believed to be strongly associated with the dopaminergic system of the brain's reward system (as in the case of cocaine and amphetamines). Some claim that it is a [[Habit habitual means to avoid undesired activity, but typically it is only so to a clinical level in individuals who have emotional, social, or psychological dysfunctions (psychological addiction is defined as such), replacing normal positive stimuli not otherwise attained.
It is considered possible to be both psychologically and physically dependent at the same time. Some doctors make little distinction between the two types of addiction, since the result, substance abuse, is the same. However, the cause and characteristics of each of the two types of addiction is quite different, as is the type of treatment preferred.
Psychological dependence does not have to be limited only to substances; even activities and behavioral patterns can be considered addictions, if they become uncontrollable, e.g. gambling, Internet addiction, computer addiction, sexual addiction/pornography addiction, eating, self-harm, vandalism or work addiction.

# Addiction and drug control legislation
Most countries have legislation which brings various drugs and drug-like substances under the control of licensing systems. Typically this legislation covers any or all of the opiates, amphetamines, cannabinoids, cocaine, barbiturates, hallucinogens (tryptamines, LSD, phencyclidine(PCP), psilocybin) and a variety of more modern synthetic drugs, and unlicensed production, supply or possession may be a criminal offense.
Usually, however, drug classification under such legislation is not related simply to addictiveness. The substances covered often have very different addictive properties. Some are highly prone to cause physical dependency, whilst others rarely cause any form of compulsive need whatsoever.  Typically nicotine (in the form of tobacco) is regulated extremely loosely, if at all, although it is well-known as one of the most addictive substances ever discovered.
Also, although the legislation may be justifiable on moral grounds to some, it can make addiction or dependency a much more serious issue for the individual. Reliable supplies of a drug become difficult to secure as illegally produced substances may have contaminants. Withdrawal from the substances or associated contaminants can cause additional health issues and the individual becomes vulnerable to both criminal abuse and legal punishment. Criminal elements that can be involved in the profitable trade of such substances can also cause physical harm to users.

# Methods of care
Early editions of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) described addiction as a physical dependency to a substance that resulted in withdrawal symptoms in its absence. Recent editions, including DSM-IV, have moved toward a diagnostic instrument that classifies such conditions as dependency, rather than addiction. The American Society of Addiction Medicine recommends treatment for people with chemical dependency based on patient placement criteria (currently listed in PPC-2), which attempt to match levels of care according to clinical assessments in six areas, including:
- Acute intoxication and/or withdrawal potential
- Biomedical conditions or complications
- Emotional/behavioral conditions or complications
- Treatment acceptance/resistance
- Relapse potential
- Recovery environment
Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index to assess the severity of problems related to substance use. The index assesses problems in six areas: medical, employment/support, alcohol and other drug use, legal, family/social, and psychiatric.
While addiction or dependency is related to seemingly uncontrollable urges, and arguably could have roots in genetic predispositions, treatment of dependency is conducted by a wide range of medical and allied professionals, including Addiction Medicine specialists, psychiatrists, and appropriately trained nurses, social workers, and counselors. Early treatment of acute withdrawal often includes medical detoxification, which can include doses of anxiolytics or narcotics to reduce symptoms of withdrawal. An experimental drug, ibogaine, is also proposed to treat withdrawal and craving. Alternatives to medical detoxification include acupuncture detoxification. In chronic opiate addiction, a surrogate drug such as methadone is sometimes offered as a form of opiate replacement therapy. But treatment approaches universal focus on the individual's ultimate choice to pursue an alternate course of action.
Therapists often classify patients with chemical dependencies as either interested or not interested in changing. Treatments usually involve planning for specific ways to avoid the addictive stimulus, and therapeutic interventions intended to help a client learn healthier ways to find satisfaction. Clinical leaders in recent years have attempted to tailor intervention approaches to specific influences that affect addictive behavior, using therapeutic interviews in an effort to discover factors that led a person to embrace unhealthy, addictive sources of pleasure or relief from pain.
From the applied behavior analysis literature and the behavioral psychology literature several evidenced based intervention programs have emerged (1) behavioral maritial therapy (2) community reinforcement approach (3) cue exposure therapy and (4) contingency management stategies (see O'Donohue, W., Ferguson, K.E. (2006) Evidence-Based Practice in Psychology and Behavior Analysis. The Behavior Analyst Today. vol 7(3). pp.335-350
 and
Chambless, D. L. et al. (1996). An update on empirically validated therapies. Clinical Psychology, 49, 5-14 ). In addition, the same author suggest that Social skills training adjunctive to inpatient treatment of alcohol dependence is probably efficacious.

# Diverse explanations
Several explanations (or "models") have been presented to explain addiction. These divide, more or less, into the models which stress biological or genetic causes for addiction, and those which stress social or purely psychological causes. Of course there are also many models which attempt to see addiction as both a physiological and a psycho-social phenomenon.
- The disease model of addiction holds that addiction is a disease, coming about as a result of either the impairment of neurochemical or behavioral processes, or of some combination of the two. Within this model, addictive disease is treated by specialists in Addiction Medicine. Within the field of medicine, the American Medical Association, National Association of Social Workers, and American Psychological Association all have policies which are predicated on the theory that addictive processes represent a disease state. Most treatment approaches, as well, are based on the idea that dependencies are behavioral dysfunctions, and, therefore, contain, at least to some extent, elements of physical or mental disease. Organizations such as the American Society of Addiction Medicine believe the research-based evidence for addiction's status as a disease is overwhelming.
- The genetic model posits a genetic predisposition to certain behaviors. It is frequently noted that certain addictions "run in the family," and while researchers continue to explore the extent of genetic influence, many researchers argue that there is strong evidence that genetic predisposition is often a factor in dependency.
- The experiential model devised by Stanton Peele argues that addictions occur with regard to experiences generated by various involvements, whether drug-induced or not.  This model is in opposition to the disease, genetic, and neurobiological approaches.  Among other things, it proposes that addiction is both more temporary or situational than the disease model claims, and is often outgrown through natural processes.
- The opponent-process model generated by Richard Soloman states that for every psychological event A will be followed by its opposite psychological event B.  For example, the pleasure one experiences from heroin is followed by an opponent process of withdrawal, or the terror of jumping out of an airplane is rewarded with intense pleasure when the parachute opens. This model is related to the opponent process color theory.  If you look at the color red then quickly look at a gray area you will see green.  There are many examples of opponent processes in the nervous system including taste, motor movement, touch, vision, and hearing. Opponent-processes occurring at the sensory level may translate "down-stream" into addictive or habit-forming behavior.
- The allostatic(stability through change) model generated by George Koob and Michel LeMoal is a modification of the opponent process theory where continued use of a drug leads to a spiralling of uncontrolled use, negative emotional states and withdrawal and a shift into use to  new allostatic set point which is lower than that maintained before use of the drug (Koob and LeMoal, 2001; Koob and LeMoal, 2006).
- The cultural model recognizes that the influence of culture is a strong determinant of whether or not individuals fall prey to certain addictions. For example, alcoholism is rare among Saudi Arabians, where obtaining alcohol is difficult and using alcohol is prohibited. In North America, on the other hand, the incidence of gambling addictions soared in the last two decades of the 20th century, mirroring the growth of the gaming industry. Half of all patients diagnosed as alcoholic are born into families where alcohol is used heavily, suggesting that familiar influence, genetic factors, or more likely both, play a role in the development of addiction. What also needs to be noted is that when people don't gain a sense of moderation through their development they can be just as likely, if not more, to abuse substances than people born into alcoholic families.
- The moral model states that addictions are the result of human weakness, and are defects of character. Those who advance this model do not accept that there is any biological basis for addiction. They often have scant sympathy for people with serious addictions, believing either that a person with greater moral strength could have the force of will to break an addiction, or that the addict demonstrated a great moral failure in the first place by starting the addiction. The moral model is widely applied to dependency on illegal substances, perhaps purely for social or political reasons, but is no longer widely considered to have any therapeutic value. Elements of the moral model, especially a focus on individual choices, have found enduring roles in other approaches to the treatment of dependencies.
- The habit model proposed by Thomas Szasz questions the very concept of "addiction." He argues that addiction is a metaphor, and that the only reason to make the distinction between habit and addiction "is to persecute somebody." (Szasz, 1973). Cf also the life-process model of addiction.
- Finally, the blended model attempts to consider elements of all other models in developing a therapeutic approach to dependency. It holds that the mechanism of dependency is different for different individuals, and that each case must be considered on its own merits.

# Neurobiological basis
The development of addiction is thought to involve a simultaneous process of 1) increased focus on and engagement in a particular behavior and 2) the attenuation or "shutting down" of other behaviors. For example, under certain experimental circumstances such as social deprivation and boredom, animals allowed the unlimited ability to self-administer certain psychoactive drugs will show such a strong preference that they will forgo food, sleep, and sex for continued access. The neuro-anatomical correlate of this is that the brain regions involved in driving goal-directed behavior grow increasingly selective for particular motivating stimuli and rewards, to the point that the brain regions involved in the inhibition of behavior can no longer effectively send "stop" signals. A good analogy is to imagine flooring the gas pedal in a car with very bad brakes. In this case, the limbic system is thought to be the major "driving force" and the orbitofrontal cortex is the substrate of the top-down inhibition.
A specific portion of the limbic circuit known as the mesolimbic dopaminergic system is hypothesized to play an important role in translation of motivation to motor behavior- and reward-related learning in particular.  It is typically defined as the ventral tegmental area (VTA), the nucleus accumbens, and the bundle of dopamine-containing fibers that are connecting them. This system is commonly implicated in the seeking out and consumption of rewarding stimuli or events, such as sweet-tasting foods or sexual interaction. However, its importance to addiction research goes beyond its role in "natural" motivation:  while the specific site or mechanism of action may differ, all known drugs of abuse have the common effect in that they elevate the level of dopamine in the nucleus accumbens. This may happen directly, such as through blockade of the dopamine re-uptake mechanism (see cocaine). It may also happen indirectly, such as through stimulation of the dopamine-containing neurons of the VTA that synapse onto neurons in the accumbens (see opiates). The euphoric effects of drugs of abuse are thought to be a direct result of the acute increase in accumbal dopamine.
The human body has a natural tendency to maintain homeostasis, and the central nervous system is no exception. Chronic elevation of dopamine will result in a decrease in the number of dopamine receptors available in a process known as downregulation. The decreased number of receptors changes the permeability of the cell membrane located post-synaptically, such that the post-synaptic neuron is less excitable- i.e.: less able to respond to chemical signaling with an electrical impulse, or action potential. It is hypothesized that this dulling of the responsiveness of the brain's reward pathways contributes to the inability to feel pleasure, known as anhedonia, often observed in addicts. The increased requirement for dopamine to maintain the same electrical activity is the basis of both physiological tolerance and withdrawal associated with addiction.
Downregulation can be classically conditioned. If a behavior consistently occurs in the same environment or contingently with a particular cue, the brain will adjust to the presence of the conditioned cues by decreasing the number of available receptors in the absence of the behavior. It is thought that many drug overdoses are not the result of a user taking a higher dose than is typical, but rather that the user is administering the same dose in a new environment.
In cases of physical dependency on depressants of the central nervous system such as opioids, barbiturates, or alcohol, the absence of the substance can lead to symptoms of severe physical discomfort. Withdrawal from alcohol or sedatives such as barbiturates or benzodiazepines (valium-family) can result in seizures and even death. By contrast, withdrawal from opioids, which can be extremely uncomfortable, is rarely if ever life-threatening. In cases of dependence and withdrawal, the body has become so dependent on high concentrations of the particular chemical that it has stopped producing its own natural versions (endogenous ligands) and instead produces opposing chemicals. When the addictive substance is withdrawn, the effects of the opposing chemicals can become overwhelming. For example, chronic use of sedatives (alcohol, barbiturates, or benzodiazepines) results in higher chronic levels of stimulating neurotransmitters such as glutamate. Very high levels of glutamate kill nerve cells, a phenomenon called excitatory neurotoxicity.

# Criticism
Levi Bryant has criticized the term and concept of addiction as counterproductive in psychotherapy as it defines a patient's identity and makes it harder to become a non-addict.  "The signifier 'addict' doesn't simply describe what I am, but initiates a way of relating to myself that informs how I relate to others."
A stronger form of criticism comes from Thomas Szasz, who denies that addiction is a psychiatric problem.  In many of his works, he argues that addiction is a choice, and that a drug addict is one who simply prefers a socially taboo substance rather than, say, a low risk lifestyle.  In Our Right to Drugs, Szasz cites the biography of Malcolm X to corroborate his economic views towards addiction: Malcolm claimed that quitting cigarettes was harder than shaking his heroin addiction.  Szasz postulates that humans always have a choice, and it is foolish to call someone an 'addict' just because they prefer a drug induced euphoria to a more popular and socially welcome lifestyle.Therefore, being 'addicted' to a substance is no different from being 'addicted' to a job at which you work everyday.
Szasz and Bryant are not alone in questioning the standard view of addiction. Professor John Booth Davies at the University of Strathclyde has argued in his book The Myth of Addiction that 'people take drugs because they want to and because it makes sense for them to do so given the choices available' as opposed to the view that 'they are compelled to by the pharmacology of the drugs they take'. . He uses an adaption of attribution theory (what he calls the theory of functional attributions) to argue that the statement 'I am addicted to drugs' is functional, rather than veridical. Stanton Peele has put forward similar views.
Experimentally, Bruce K. Alexander used the classic experiment of Rat Park to show that 'addicted' behaviour in rats only occurred when the rats had no other options. When other options and behavioural opportunities were put in place, the rats soon showed far more complex behaviours.

# Casual addiction
The word addiction is also sometimes used colloquially to refer to something for which a person has a passion, such as books, chocolate, work, the web, running, or eating.