Sexual addiction, also known as sex addiction, is a state characterized by [[compulsive]] participation or engagement in [[Human sexual activity|sexual activity]], particularly [[sexual intercourse]], despite negative consequences. Proponents of a [[diagnostic model]] for sexual addiction, as defined here, consider it to be one of several sex-related disorders within an umbrella concept known as [[hypersexual disorder]]. The term "sexual dependence" is also used to refer to people who report being unable to control their [[sexual urges]], behaviors, or thoughts. Related models of pathological sexual behavior include [[hypersexuality]] (nymphomania and satyriasis), [[erotomania]], [[Don Juanism]] (or Don Juanitaism), and [[paraphilia]]-related disorders.

The concept of sexual addiction is contentious. There is considerable debate amongst [[psychiatrists]], psychologists, [[sexologist]]s, and other specialists whether compulsive sexual behavior constitutes an addiction, and therefore its classification and possible diagnosis. , sexual addiction is not a clinical diagnosis in either the [[Diagnostic and Statistical Manual of Mental Disorders|DSM]] or [[International Statistical Classification of Diseases and Related Health Problems|ICD]] medical classifications of diseases and medical disorders. Some argue that applying such concepts to normal behaviors such as sex, can be problematic, and suggest that applying medical models such as addiction to human sexuality can serve to [[Slut-shaming|pathologise normal behavior]] and cause harm

Neuroscientists, pharmacologists, molecular biologists, and other researchers in related fields have identified the [[transcription factor|transcriptional]] and [[epigenetic]] mechanisms of addiction [[pathophysiology]]. Diagnostic models, which use the pharmacological model of addiction (this model associates addiction with drug-related concepts, particularly [[physical dependence]], [[drug withdrawal]], and [[drug tolerance]]), do not currently include diagnostic criteria to identify sexual addictions in a clinical setting. In the brain disease model of addiction, which uses neuropsychological concepts to characterize addictions, sexual addictions are identifiable and well-characterized. In this model, [[addictive drugs]] are characterized as those which are both [[reinforcing]] and [[reward system|rewarding]]. Addictive behaviors (those which can induce a compulsive state) are similarly identified and characterized by their rewarding and reinforcing properties.

In "Sexual Addiction and Compulsivity", authors Taylor and Francis argue that: "Obsessive sexual behavior illness is defined by a continual pattern of failure to control intense, repetitive sexual impulses or urges."

The ICD, DSM and CCMD list promiscuity as a prevalent and problematic symptom for [[Borderline personality disorder|Borderline Personality Disorder]]. Individuals with this diagnosis sometimes engage in sexual behaviors which can appear out of control causing distress to the individual or attracting negative reception from others. There is therefore a risk that a person presenting with sex addiction, may in fact be suffering from Borderline Personality Disorder. This may lead to inappropriate or incomplete treatment

Internet sex addiction, also known as cybersex addiction, has been proposed as a sexual addiction characterized by virtual Internet sexual activity that causes serious negative consequences to one's physical, mental, social, and/or financial well-being. It may also be considered a subset of the theorized Internet addiction disorder. Internet sex addiction manifests various behaviours: reading erotic stories; viewing, downloading or trading online pornography; online activity in adult fantasy chat rooms; cybersex relationships; masturbation while engaged in online activity that contributes to one's sexual arousal; the search for offline sexual partners and information about sexual activity.

There is an ongoing debate in the medical community concerning the insufficient studies, and of those, their quality, or lack thereof, and the resulting analysis and conclusions drawn from them, such as they are. So far, without repeatable, meaningful, measurable, and quantifiable analysis, no medical community wide acceptably reasonable standards, a definition, have been drawn yet.

Hence, internet sex addiction, just like it's umbrella sexual addiction, is still not listed in the DSM-5, which is commonly used by psychiatrists in the United States for diagnosing patients problems in a standard uniform way.

Internet addiction disorder, more commonly called problematic Internet use (PIU), refers to excessive Internet use that interferes with daily life.

Addiction is defined by Webster Dictionary as a "compulsive need for and use of a habit-forming substance characterized by tolerance and by well-defined physiological symptoms upon withdrawal; broadly: persistent compulsive use of a substance known by the user to be harmful".

Problematic Internet use is also called compulsive Internet use (CIU), Internet overuse, problematic computer use, or pathological computer use (PCU), problematic Internet use (PIU), or Internet addiction disorder (IAD)). Another commonly associated pathology is video game addiction, or Internet gaming disorder (IGD).

Hypoactive sexual desire disorder (HSDD) or inhibited sexual desire (ISD) is considered a sexual dysfunction and is characterized as a lack or absence of sexual fantasies and desire for sexual activity, as judged by a clinician. For this to be regarded as a disorder, it must cause marked distress or interpersonal difficulties and not be better accounted for by another mental disorder, a drug (legal or illegal), some other medical condition, or asexuality. A person with ISD will not start, or respond to their partner's desire for, sexual activity.

There are various subtypes. HSDD can be general (general lack of sexual desire) or situational (still has sexual desire, but lacks sexual desire for current partner), and it can be acquired (HSDD started after a period of normal sexual functioning) or lifelong (the person has always had no/low sexual desire.)

HSDD has garnered much criticism, primarily by asexual activists. They point out that HSDD puts asexuality in the same position homosexuality was from 1974-1987. The DSM at that time recognised 'ego-dystonic homosexuality' as a disorder, defined as sexual interest in the same sex that caused significant distress. The DSM itself officially recognized this as unnecessarily pathologizing homosexuality and removed it as a disorder in 1987.

Sexual sadism disorder is the condition of experiencing sexual arousal in response to the extreme pain, suffering or humiliation of others. Several other terms have been used to describe the condition, and the condition may overlap with other conditions that involve inflicting pain. It is distinct from situations in which consenting individuals use mild or simulated pain or humiliation for sexual excitement. The words "sadism" and "" are derived from Marquis de Sade.

HSDD was listed under the Sexual and Gender Identity Disorders of the DSM-IV. In the DSM-5, it was split into male hypoactive sexual desire disorder and female sexual interest/arousal disorder. It was first included in the DSM-III under the name inhibited sexual desire disorder, but the name was changed in the DSM-III-R. Other terms used to describe the phenomenon include sexual aversion and sexual apathy. More informal or colloquial terms are "frigidity" and "frigidness".

Sexual obsessions are obsessions with sexual activity. In the context of obsessive-compulsive disorder (OCD), these are extremely common, and can become extremely debilitating, making the person ashamed of the symptoms and reluctant to seek help. As preoccupation with sexual matters, however, does not only occur as a symptom of OCD, they may be enjoyable in other contexts (i.e. sexual fantasy).

Ego-dystonic sexual orientation is an ego-dystonic mental disorder characterized by having a sexual orientation or an attraction that is at odds with one's idealized self-image, causing anxiety and a desire to change one's orientation or become more comfortable with one's sexual orientation. It describes not innate sexual orientation itself, but a conflict between the sexual orientation one wishes to have and the sexual orientation one actually possesses.

The World Health Organization (WHO) lists ego-dystonic sexual orientation in the ICD-10, as a disorder of sexual development and orientation. The WHO diagnosis covers when gender identity or sexual orientation is clear, yet a patient has another behavioural or psychological disorder which makes that patient want to change it. The diagnostic manual notes that a sexual orientation is not a disorder in itself. The World Health Organization (WHO) notes that any particular sexual orientation (heterosexuality, homosexuality, or bisexuality) is not a mental disorder by and of itself.

Similarly, the American Psychological Association has officially opposed the category of ego-dystonic homosexuality since 1987. In 2007, a task force of the American Psychological Association undertook a thorough review of the existing research on the efficacy of reparative therapy for. Their report noted that there was very little methodologically sound research on sexual orientation change efforts (SOCEs) and that the "results of scientifically valid research indicate that it is unlikely that individuals will be able to reduce same-sex attractions or increase other-sex sexual attractions through SOCE." In addition, the task force found that "there are no methodologically sound studies of recent SOCE that would enable the task force to make a definitive statement about whether or not recent SOCE is safe or harmful and for whom." The diagnostic category of "ego-dystonic homosexuality" was removed from the American Psychiatric Association's DSM in 1987 (with the publication of the DSM-III-R). Sexual disorders are still present in the DSM under the category of "sexual disorder not otherwise specified". One of the disorders under this category is "persistent and marked distress about one’s sexual orientation”, which can be considered similar to what WHO describes as ego-dystonic sexual orientation.

The Medical Council of India uses the WHO classification of ego-dystonic sexual orientation. The "Chinese Classification and Diagnostic Criteria of Mental Disorders" includes ego-dystonic homosexuality.

Psychological dependence is a form of dependence that involves emotional–motivational withdrawal symptoms (e.g., a state of unease or dissatisfaction, a reduced capacity to experience pleasure, or anxiety) upon cessation of drug use or engagement in certain behaviors. Physical and psychological dependence are sometimes classified as a facet or component of addiction, such as in the DSM-IV-TR; however, some drugs which produce dependence syndromes do not produce addiction, and vice versa, in humans. Addiction and psychological dependence are both mediated through reinforcement, a form of operant conditioning, but are associated with different forms of reinforcement. Addiction is a compulsion for rewarding stimuli that is mediated through positive reinforcement. Psychological dependence, which is mediated through negative reinforcement, involves a desire to use a drug or perform a behavior to avoid the unpleasant withdrawal syndrome that results from cessation of exposure to it.

Psychological dependence develops through consistent and frequent exposure to a stimulus. Behaviors which can produce observable psychological withdrawal symptoms (i.e., cause psychological dependence) include physical exercise, shopping, sex and self-stimulation using pornography, and eating food with high sugar or fat content, among others. Behavioral therapy is typically employed to help individuals overcome psychological dependence upon drugs or maladaptive behaviors that produce psychological dependence.

In the DSM-5 all paraphilia disorders can be diagnosed by two main criteria that are referred to criteria A and criteria B respectively. The A and B criteria include a duration in which the behavior must be present for (typically 6 months) and specific details of actions or thoughts that are correlated specifically with the respective disorder being diagnosed.

Psychosexual disorder is a term which may simply refer to a sexual problem that is psychological, rather than physiological in origin. "Psychosexual disorder" was a term used in . The term of psychosexual disorder (Turkish: "Psikoseksüel bozukluk") used by the TAF for homosexuality as a reason to ban the LGBT people from military service.

The DSM definition of addiction can be boiled down to compulsive use of a substance (or engagement in an activity) despite ongoing negative consequences. The medical community makes a distinction between physical dependence (characterized by symptoms of physical withdrawal symptoms, like tremors and sweating) and psychological dependence (emotional-motivational withdrawal symptoms). Physical dependence is simply needing a substance to function. Humans are all physically dependent upon oxygen, food and water. A drug can cause physical dependence and not psychological dependence (for example, some blood pressure medications, which can produce fatal withdrawal symptoms if not tapered) and some can cause psychological dependence without physical dependence (the withdrawal symptoms associated with cocaine are all psychological, there is no associated vomiting or diarrhea as there is with opiate withdrawal).

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT and adults such as the CAGE.

Compulsions and addictions are intertwined and reward is one major distinction between an addiction and a compulsion (as it is experienced in obsessive-compulsive disorder). An addiction is, by definition, a form of compulsion, and both addictions and compulsions involve operant reinforcement; however, in addiction, the desire and motivation to use a substance or engage in a behavior arises because it is rewarding (i.e., the compulsions that occur in addiction develop through positive reinforcement). In contrast, someone who experiences a compulsion as part of obsessive-compulsive disorder may not perceive anything rewarding from acting on the compulsion. Often, it is a way of dealing with the obsessive part of the disorder, resulting in a feeling of relief (i.e., compulsions may also arise through negative reinforcement).

Deep brain stimulation to the nucleus accumbens, a region in the brain involved heavily in addiction and reinforcement learning, has proven to be an effective treatment of obsessive compulsive disorder.

Physical dependence on a substance is defined by the appearance of characteristic physical 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.

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 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 from the factors behind addictions described in this article. It has been reported, however, that patients with eating disorders can successfully be treated with the same non-pharmacological protocols used in patients with chemical addiction disorders.

Gambling is another potentially addictive behavior with some biological overlap. Conversely gambling urges have emerged with the administration of Mirapex (pramipexole), a dopamine agonist.

The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.

Paraphilia (previously known as sexual perversion and sexual deviation) is the experience of intense sexual arousal to atypical objects, situations, fantasies, behaviors, or individuals. Such attraction may be labeled sexual fetishism. No consensus has been found for any precise border between unusual sexual interests and paraphilic ones. There is debate over which, if any, of the paraphilias should be listed in diagnostic manuals, such as the "Diagnostic and Statistical Manual of Mental Disorders" (DSM) or the International Classification of Diseases (ICD).

The number and taxonomy of paraphilia is under debate; one source lists as many as 549 types of paraphilia. The DSM-5 has specific listings for eight paraphilic disorders. Several sub-classifications of the paraphilias have been proposed, and some argue that a fully dimensional, spectrum or complaint-oriented approach would better reflect the evidence.

Research by governments in Australia led to a universal definition for that country which appears to be the only research-based definition not to use diagnostic criteria: "Problem gambling is characterized by many difficulties in limiting money and/or time spent on gambling which leads to adverse consequences for the gambler, others, or for the community." The University of Maryland Medical Center defines pathological gambling as "being unable to resist impulses to gamble, which can lead to severe personal or social consequences".

Most other definitions of problem gambling can usually be simplified to any gambling that causes harm to the gambler or someone else in any way; however, these definitions are usually coupled with descriptions of the type of harm or the use of diagnostic criteria. The "DSM-V" has since reclassified pathological gambling as "gambling disorder" and has listed the disorder under substance-related and addictive disorders rather than impulse-control disorders. This is due to the symptomatology of the disorder resembling an addiction not dissimilar to that of substance-abuse. There are both environmental and genetic factors that can influence on gambler and cause some type of addiction. In order to be diagnosed, an individual must have at least four of the following symptoms in a 12-month period:

- Needs to gamble with increasing amounts of money in order to achieve the desired excitement

- Is restless or irritable when attempting to cut down or stop gambling

- Has made repeated unsuccessful efforts to control, cut back, or stop gambling

- Is often preoccupied with gambling (e.g., having persistent thoughts of reliving past gambling experiences, handicapping or planning the next venture, thinking of ways to get money with which to gamble)

- Often gambles when feeling distressed (e.g., helpless, guilty, anxious, depressed)

- After losing money gambling, often returns another day to get even ("chasing" one's losses)

- Lies to conceal the extent of involvement with gambling

- Has jeopardized or lost a significant relationship, job, education or career opportunity because of gambling

- Relies on others to provide money to relieve desperate financial situations caused by gambling

The ICD-10 defines fetishism as a reliance on non-living objects for sexual arousal and satisfaction. It is only considered a disorder when fetishistic activities are the foremost source of sexual satisfaction, and become so compelling or unacceptable as to cause distress or interfere with normal sexual intercourse. The ICD's research guidelines require that the preference persists for at least six months, and is markedly distressing or acted on.

Under the DSM-5, fetishism is sexual arousal from nonliving objects or specific nongenital body parts, excluding clothes used for cross-dressing (as that falls under transvestic disorder) and sex toys that are designed for genital stimulation. In order to be diagnosed as "fetishistic disorder", the arousal must persist for at least six months and cause significant psychosocial distress or impairment in important areas of their life. In the DSM-IV, sexual interest in body parts was distinguished from fetishism under the name partialism (diagnosed as Paraphilia NOS), but it was merged with fetishistic disorder for the DSM-5.

The ReviseF65 project has campaigned for the ICD diagnosis to be abolished completely to avoid stigmatizing fetishists. Sexologist Odd Reiersøl argues that distress associated with fetishism is often caused by shame, and that being subject to diagnosis only exacerbates that. He suggests that, in cases where the individual fails to control harmful behavior, they instead be diagnosed with a personality or impulse control disorder.

Sexual maturation disorder is a disorder of anxiety or depression related to an uncertainty about one's gender identity or sexual orientation. The World Health Organization (WHO) lists sexual maturation disorder in the ICD-10, under "Psychological and behavioural disorders associated with sexual development and orientation".

Sexual orientation, by itself, is not a disorder and is not classified under this heading. It differs from ego-dystonic sexual orientation where the sexual orientation or gender identity is repressed or denied.

In a review of 48 cases of clinical fetishism, fetishes included clothing (58.3%), rubber and rubber items (22.9%), footwear (14.6%), body parts (14.6%), leather (10.4%), and soft materials or fabrics (6.3%). A 2007 study counted members of Internet discussion groups with the word "fetish" in their name. Of the groups about body parts or features, 47% belonged to groups about feet (foot fetishism), 9% about body fluids, 9% about body size, 7% about hair (hair fetish), and 5% about muscles (muscle worship). Less popular groups focused on navels (navel fetishism), legs, body hair, mouth, and nails, among other things. Of the groups about clothing, 33% belonged to groups about clothes worn on the legs or buttocks (such as stockings or skirts), 32% about footwear (shoe fetishism), 12% about underwear (underwear fetishism), and 9% about whole-body wear such as jackets. Less popular object groups focused on headwear, stethoscopes, wristwear, and diapers (diaper fetishism).

Sexual dysfunction (or sexual malfunction or sexual disorder) is difficulty experienced by an individual or a couple during any stage of a normal sexual activity, including physical pleasure, desire, preference, arousal or orgasm. According to the DSM-5, sexual dysfunction requires a person to feel extreme distress and interpersonal strain for a minimum of 6 months (excluding substance or medication-induced sexual dysfunction). Sexual dysfunctions can have a profound impact on an individual's perceived quality of sexual life. The term "sexual disorder" may not only refer to physical sexual dysfunction, but to paraphilias as well; this is sometimes termed "disorder of sexual preference".

A thorough sexual history and assessment of general health and other sexual problems (if any) are very important. Assessing performance anxiety, guilt, stress and worry are integral to the optimal management of sexual dysfunction. Many of the sexual dysfunctions that are defined are based on the human sexual response cycle, proposed by William H. Masters and Virginia E. Johnson, and then modified by Helen Singer Kaplan.

Pedophilia or paedophilia is a psychiatric disorder in which an adult or older adolescent experiences a primary or exclusive sexual attraction to prepubescent children. Although girls typically begin the process of puberty at age 10 or 11, and boys at age 11 or 12, criteria for pedophilia extend the cut-off point for prepubescence to age 13. A person who is diagnosed with pedophilia must be at least 16 years old, and at least five years older than the prepubescent child, for the attraction to be diagnosed as pedophilia.

Pedophilia is termed pedophilic disorder in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), and the manual defines it as a paraphilia involving intense and recurrent sexual urges towards and fantasies about prepubescent children that have either been acted upon or which cause the person with the attraction distress or interpersonal difficulty. The International Classification of Diseases (ICD-10) defines it as a sexual preference for children of prepubertal or early pubertal age.

In popular usage, the word "pedophilia" is often applied to any sexual interest in children or the act of child sexual abuse. This use conflates the sexual attraction to prepubescent children with the act of child sexual abuse, and fails to distinguish between attraction to prepubescent and pubescent or post-pubescent minors. Researchers recommend that these imprecise uses be avoided because although people who commit child sexual abuse are sometimes pedophiles, child sexual abuse offenders are not pedophiles unless they have a primary or exclusive sexual interest in prepubescent children, and some pedophiles do not molest children.

Pedophilia was first formally recognized and named in the late 19th century. A significant amount of research in the area has taken place since the 1980s. Although mostly documented in men, there are also women who exhibit the disorder, and researchers assume available estimates underrepresent the true number of female pedophiles. No cure for pedophilia has been developed, but there are therapies that can reduce the incidence of a person committing child sexual abuse. The exact causes of pedophilia have not been conclusively established. Some studies of pedophilia in child sex offenders have correlated it with various neurological abnormalities and psychological pathologies. In the United States, following "Kansas v. Hendricks", sex offenders who are diagnosed with certain mental disorders, particularly pedophilia, can be subject to indefinite civil commitment.