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).

Many different types of medication can create/induce pure OCD in patients that have never had symptoms before. A new chapter about OCD in the DSM-5 (2013) now specifically includes drug-induced OCD.

Second generation atypical anti-psychotics, such as Olanzapine (Zyprexa), have been proven to induce de-novo OCD in patients.

In psychology, relationship obsessive–compulsive disorder (ROCD) is a form of obsessive-compulsive disorder focusing on intimate relationships (whether romantic or non-romantic). Such obsessions can become extremely distressing and debilitating, having negative impacts on relationships functioning.

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.

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.

Obsessive-compulsive disorder comprises thoughts, images or urges that are unwanted, distressing, interfere with a person's life and that are commonly experienced as contradicting a persons' beliefs and values. Such intrusive thoughts are frequently followed by compulsive behaviors aimed at "neutralizing" the feared consequence of the intrusions and temporarily relieve the anxiety caused by the obsessions. Attempts to suppress or "neutralize" obsessions increase rather than decrease the frequency and distress caused by the obsessions.

Common obsessive themes include fear of contamination, fears about being responsible for harming the self or others, doubts, and orderliness. However, people with OCD can also have religious and sexual obsessions. Some people with OCD may experience obsessions relating to the way they feel in an ongoing relationship or the way they felt in past relationships (ROCD). Repetitive thought about a person's feelings in intimate relationships may occur in the natural course of the relationship development; however, in ROCD such preoccupations are unwanted, intrusive, chronic and disabling.

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.

Transvestic fetishism is a psychiatric diagnosis applied to those who are thought to have an excessive sexual or erotic interest in cross-dressing; this interest is often expressed in autoerotic behavior. It differs from cross-dressing for entertainment or other purposes that do not involve sexual arousal, and is categorized as a paraphilia in the Diagnostic and Statistical Manual of the American Psychiatric Association. (Sexual arousal in response to donning sex-typical clothing is homeovestism.)

Courtship disorder is a theoretical construct in sexology in which a certain set of paraphilias are seen as specific instances of anomalous courtship instincts in men. The specific paraphilias are biastophilia (paraphilic rape), exhibitionism, frotteurism, telephone scatologia, and voyeurism. According to the "courtship disorder hypothesis", there is a species-typical courtship process in human males consisting of four phases, and anomalies in different phases result in one of these paraphilic sexual interests. That is, instead of being independent paraphilias, this theory sees these sexual interests as individual symptoms of a single underlying disorder.

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.

Primarily cognitive obsessive-compulsive disorder (also commonly called "primarily obsessional OCD", purely obsessional OCD, Pure-O, OCD without overt compulsions or with covert compulsions) is a lesser-known form or manifestation of OCD. For people with primarily obsessional OCD, there are fewer observable compulsions, compared to those commonly seen with the typical form of OCD (checking, counting, hand-washing, etc.). While ritualizing and neutralizing behaviors do take place, they are mostly cognitive in nature, involving mental avoidance and excessiverumination. Primarily obsessional OCD often takes the form of intrusive thoughts of a distressing or violent nature.

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.

People with hypersexual disorder experience multiple, unsuccessful attempts to control or diminish the amount of time spent engaging in sexual fantasies, urges, and behaviors in response to dysphoric mood states or stressful life events.

For a valid diagnosis of hypersexual disorder to be established, symptoms must persist for a period of at least 6 months and occur independently of a use mania or a medical condition.

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.

Sexophobia is the fear of sexual organs or sexual activities and, in a larger sense, the fear of sexuality. As such, it can be applied to the attitude of a person based on his or her educational background, personal experience and psyche, or to the general position of collective entities like religious groups, institutions or states.

Intrusive thoughts may involve violent obsessions about hurting others or themselves. They can be related to primarily obsessional obsessive compulsive disorder. These thoughts can include harming a child; jumping from a bridge, mountain, or the top of a tall building; urges to jump in front of a train or automobile; and urges to push another in front of a train or automobile. Rachman's survey of healthy college students found that virtually all of them had intrusive thoughts from time to time, including:

- causing harm to elderly people

- imagining or wishing harm upon someone close to oneself

- impulses to violently attack, hit, harm or kill a person, small child, or animal

- impulses to shout at or abuse someone, or attack and violently punish someone, or say something rude, inappropriate, nasty, or violent to someone.

These thoughts are part of being human, and need not ruin quality of life. Treatment is available when the thoughts are associated with OCD and become persistent, severe, or distressing.

A variant of aggressive intrusive thoughts is L'appel du vide, or the call of the void. Sufferers of "L'appel du vide" generally describe the condition as manifesting in certain situations, normally as a wish or brief desire to jump from a high location.

Many people experience the type of bad or unwanted thoughts that people with more troubling intrusive thoughts have, but most people can dismiss these thoughts. For most people, intrusive thoughts are a "fleeting annoyance". Psychologist Stanley Rachman presented a questionnaire to healthy college students and found that virtually all said they had these thoughts from time to time, including thoughts of sexual violence, sexual punishment, "unnatural" sex acts, painful sexual practices, blasphemous or obscene images, thoughts of harming elderly people or someone close to them, violence against animals or towards children, and impulsive or abusive outbursts or utterances. Such bad thoughts are universal among humans, and have "almost certainly always been a part of the human condition".

When intrusive thoughts occur with obsessive-compulsive disorder (OCD), patients are less able to ignore the unpleasant thoughts and may pay undue attention to them, causing the thoughts to become more frequent and distressing. The thoughts may become obsessions which are paralyzing, severe, and constantly present, and can range from thoughts of violence or sex to religious blasphemy. Distinguishing them from normal intrusive thoughts experienced by many people, the intrusive thoughts associated with OCD may be anxiety provoking, irrepressible, and persistent.

How people react to intrusive thoughts may determine whether these thoughts will become severe, turn into obsessions, or require treatment. Intrusive thoughts can occur with or without compulsions. Carrying out the compulsion reduces the anxiety, but makes the urge to perform the compulsion stronger each time it recurs, reinforcing the intrusive thoughts. According to Lee Baer, suppressing the thoughts only makes them stronger, and recognizing that bad thoughts do not signify that one is truly evil is one of the steps to overcoming them. There is evidence of the benefit of acceptance as an alternative to suppression of intrusive thoughts. A study showed that those instructed to suppress intrusive thoughts experienced more distress after suppression, while patients instructed to accept the bad thoughts experienced decreased discomfort. These results may be related to underlying cognitive processes involved in OCD. However, accepting the thoughts can be more difficult for persons with OCD. In the 19th century, OCD was known as "the doubting sickness"; the "pathological doubt" that accompanies OCD can make it harder for a person with OCD to distinguish "normal" intrusive thoughts as experienced by most people, causing them to "suffer in silence, feeling too embarrassed or worried that they will be thought crazy".

The possibility that most patients suffering from intrusive thoughts will ever act on those thoughts is low. Patients who are experiencing intense guilt, anxiety, shame, and upset over these thoughts are different from those who actually act on them. The history of violent crime is dominated by those who feel no guilt or remorse; the very fact that someone is tormented by intrusive thoughts and has never acted on them before is an excellent predictor that they will not act upon the thoughts. Patients who are not troubled or shamed by their thoughts, do not find them distasteful, or who have actually taken action, might need to have more serious conditions such as psychosis or potentially criminal behaviors ruled out. According to Lee Baer, a patient should be concerned that intrusive thoughts are dangerous if the person does not feel upset by the thoughts, or rather finds them pleasurable; has ever acted on violent or sexual thoughts or urges; hears voices or sees things that others do not see; or feels uncontrollable irresistible anger.

Hypersexual disorder is a pattern of behavior involving intense preoccupation with sexual fantasies, urges and activities, leading to adverse consequences and clinically significant distress or impairment in social, occupational or other important functions. It was proposed in 2010 for inclusion in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) of the American Psychiatric Association (APA).

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".

Symptoms of genophobia can be feeling of panic, terror, and dread. Other symptoms are increased speed of heartbeat, shortness of breath, trembling/shaking, anxiety, sweating, crying, and avoidance of others.

Males with late onset gender dysphoria "frequently" display transvestic fetishism.

Some male transvestic fetishists collect women's clothing, e.g. panties, nightgowns, babydolls, bridal gowns, slips, brassieres, and other types of nightwear, lingerie, stockings, pantyhose, shoes, and boots, items of a distinct feminine look and feel. They may dress in these feminine garments and take photographs of themselves while living out their fantasies.

According to DSM-IV, this fetishism was limited to heterosexual men; however, DSM-5 does not have this restriction, and opens it to women and men with this interest, regardless of their sexual orientation.

There are two key criteria before a psychiatric diagnosis of "transvestic fetishism" is made:

1. Individuals must be sexually aroused by the act of cross-dressing.

2. Individuals must experience significant distress or impairment – socially or occupationally – because of their behavior.

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.

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."

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.

Scrupulosity is characterized by pathological guilt about moral or religious issues. It is personally distressing, objectively dysfunctional, and often accompanied by significant impairment in social functioning. It is typically conceptualized as a moral or religious form of obsessive–compulsive disorder (OCD), although this categorization is empirically disputable.

The term is derived from the Latin "scrupulum", a sharp stone, implying a stabbing pain on the conscience. Scrupulosity was formerly called "scruples" in religious contexts, but the word "scruples" now commonly refers to a troubling of the conscience rather than to the disorder.

As a personality trait, scrupulosity is a recognized diagnostic criterion for obsessive–compulsive personality disorder. It is sometimes called "scrupulousness", but that word properly applies to the positive trait of having scruples.