Paraphilia in the context of Pornography in Japan

Perversion is a form of human behavior which is far from what is considered to be orthodox or normal. Although the term perversion can refer to a variety of forms of deviation, it is most often used to describe sexual behaviors that are considered particularly abnormal, repulsive or obsessive. Perversion usually differs from "deviant behavior", in that the latter covers areas of behavior (such as petty crime) for which perversion would be too strong a term. It is often considered derogatory, and, in psychological literature, the term paraphilia has been used as a replacement for most forms of sexual perversion, though this clinical term is controversial, and deviation is sometimes used in its place.

Sexology is the scientific study of human sexuality, including human sexual interests, behaviors, and functions. The term sexology does not generally refer to the non-scientific study of sexuality, such as social criticism.

Sexologists apply tools from several academic fields, such as anthropology, biology, medicine, psychology, epidemiology, sociology, and criminology. Topics of study include sexual development (puberty), sexual orientation, gender identity, sexual relationships, sexual activities, paraphilias, and atypical sexual interests. It also includes the study of sexuality across the lifespan, including child sexuality, puberty, adolescent sexuality, and sexuality among the elderly. Sexology also spans sexuality among those with mental or physical disabilities. The sexological study of sexual dysfunctions and disorders, including erectile dysfunction and anorgasmia, are also mainstays.

Animal sexual behaviour takes many different forms, including within the same species. Common mating or reproductively motivated systems include monogamy, polygyny, polyandry, polygamy and promiscuity. Other sexual behaviour may be reproductively motivated (e.g. sex apparently due to duress or coercion and situational sexual behaviour) or non-reproductively motivated (e.g. homosexual sexual behaviour, bisexual sexual behaviour, cross-species sex, sexual arousal from objects or places, sex with dead animals, etc.).

When animal sexual behaviour is reproductively motivated, it is often termed mating or copulation; for most non-human mammals, mating and copulation occur at oestrus (the most fertile period in the mammalian female's reproductive cycle), which increases the chances of successful impregnation. Some animal sexual behaviour involves competition, sometimes fighting, between multiple males. Females often select males for mating only if they appear strong and able to protect themselves. The male that wins a fight may also have the chance to mate with a larger number of females and will therefore pass on his genes to their offspring.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), is the 2013 update to the Diagnostic and Statistical Manual of Mental Disorders, the taxonomic and diagnostic tool published by the American Psychiatric Association (APA). In 2022, a revised version (DSM-5-TR) was published. In the United States, the DSM serves as the principal authority for psychiatric diagnoses. Treatment recommendations, as well as payment by health insurance companies, are often determined by DSM classifications, so the appearance of a new version has practical importance. However, some providers instead rely on the International Statistical Classification of Diseases and Related Health Problems (ICD), and scientific studies often measure changes in symptom scale scores rather than changes in DSM-5 criteria to determine the real-world effects of mental health interventions. The DSM-5 is the only DSM to use an Arabic numeral instead of a Roman numeral in its title, as well as the only living document version of a DSM.

The DSM-5 is not a major revision of the DSM-IV-TR, but the two have significant differences. Changes in the DSM-5 include the re-conceptualization of Asperger syndrome from a distinct disorder to an autism spectrum disorder; the elimination of subtypes of schizophrenia; the deletion of the "bereavement exclusion" for depressive disorders; the renaming and reconceptualization of gender identity disorder to gender dysphoria; the inclusion of binge eating disorder as a discrete eating disorder; the renaming and reconceptualization of paraphilias, now called paraphilic disorders; the removal of the five-axis system; and the splitting of disorders not otherwise specified into other specified disorders and unspecified disorders.

Zoophilia is a paraphilia in which a person experiences a sexual fixation on non-human animals. Bestiality instead refers to cross-species sexual activity between humans and non-human animals. Due to the lack of research on the subject, it is difficult to conclude how prevalent bestiality is. Zoophilia was estimated in one study to be prevalent in 2% of the population in 2021.

Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction as a "person's inability to participate in a sexual relationship as they would wish". This definition is broad and is subject to many interpretations. A diagnosis of sexual dysfunction under the DSM-5 requires a person to feel extreme distress and interpersonal strain for a minimum of six months (except for substance- or medication-induced sexual dysfunction). Sexual dysfunction 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 important when assessing sexual dysfunction, because it is usually correlated with other psychiatric issues, such as mood disorders, eating and anxiety disorders, and schizophrenia. 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 modified by Helen Singer Kaplan.

Necrophilia, also known as necrophilism, necrolagnia, necrocoitus, necrochlesis, and thanatophilia, is sexual attraction or acts involving corpses, including both direct intercourse with corpses and sexual excitement at the thought or presence of one. It is classified as a paraphilia by the World Health Organization (WHO) in its International Classification of Diseases (ICD) diagnostic manual, as well as by the American Psychiatric Association in its Diagnostic and Statistical Manual (DSM). Reported motivations vary widely, ranging between sexual domination of a non-responsive partner, fetishization of death and corpses, and bereavement of a close sexual partner. Necrophilia can coincide with sexual roleplay of the subject instead pretending to be a corpse while their partner takes on the role of the necrophile.

In contrast to human paraphilias, many cases of animal necrophilia (also known as Davian behavior) have been observed, primarily as a result of being unable to distinguish between a receptive mate and a recently deceased one. Some species of arthropods and frogs can instead fully copulate with a recently killed mate.

Zoosadism is sexual pleasure derived from cruelty to animals. It is a paraphilia, where people are sexually aroused by torturing animals. Zoosadism is part of the Macdonald triad, a set of three behaviors that have been considered a precursor to psychopathic behavior.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), is the 2013 update to the Diagnostic and Statistical Manual of Mental Disorders, the taxonomic and diagnostic tool published by the American Psychiatric Association (APA). In 2022, a revised version (DSM-5-TR) was published. In the United States, the DSM serves as the principal authority for psychiatric diagnoses. Treatment recommendations, as well as payment by health insurance companies, are often determined by DSM classifications, so the appearance of a new version has practical importance. However, some providers instead rely on the International Classification of Diseases (ICD), and scientific studies often measure changes in symptom scale scores rather than changes in DSM-5 criteria to determine the real-world effects of mental health interventions. The DSM-5 is the only DSM to use an Arabic numeral instead of a Roman numeral in its title, as well as the only living document version of a DSM.

The DSM-5 is not a major revision of the DSM-IV-TR, but the two have significant differences. Changes in the DSM-5 include the re-conceptualization of Asperger syndrome from a distinct disorder to an autism spectrum disorder; the elimination of subtypes of schizophrenia; the deletion of the "bereavement exclusion" for depressive disorders; the renaming and reconceptualization of gender identity disorder to gender dysphoria; the inclusion of binge eating disorder as a discrete eating disorder; the renaming and reconceptualization of paraphilias, now called paraphilic disorders; the removal of the five-axis system; and the splitting of disorders not otherwise specified into other specified disorders and unspecified disorders.

Paraphilias are sexual interests in objects, situations, or individuals that are atypical. The American Psychiatric Association, in its Diagnostic and Statistical Manual, Fifth Edition (DSM), draws a distinction between paraphilias (which it describes as atypical sexual interests) and paraphilic disorders (which additionally require the experience of distress, impairment in functioning, and/or the desire to act on them with a nonconsenting person). Some paraphilias have more than one term to describe them, and some terms overlap with others. Paraphilias without DSM codes listed come under DSM 302.9, "Paraphilia NOS (Not Otherwise Specified)".

In his 2008 book on sexual pathologies, Anil Aggrawal compiled a list of 547 terms describing paraphilic sexual interests. He cautioned, however, that "not all these paraphilias have necessarily been seen in clinical setups. This may not be because they do not exist, but because they are so innocuous they are never brought to the notice of clinicians or dismissed by them. Like allergies, sexual arousal may occur from anything under the sun, including the sun."

Medroxyprogesterone acetate (MPA), also known as depot medroxyprogesterone acetate (DMPA) in injectable form and sold under the brand name Depo-Provera among others, is a hormonal medication of the progestin type. It is used as a method of birth control and as a part of menopausal hormone therapy. It is also used to treat endometriosis, abnormal uterine bleeding, paraphilia, and certain types of cancer. The medication is available both alone and in combination with an estrogen. It is taken by mouth, used under the tongue, or by injection into a muscle or fat.

Common side effects include menstrual disturbances such as absence of periods, abdominal pain, and headaches. More serious side effects include bone loss, blood clots, allergic reactions, and liver problems. Use is not recommended during pregnancy as it may harm the baby. MPA is an artificial progestogen, and as such activates the progesterone receptor, the biological target of progesterone. It also has androgenic activity and weak glucocorticoid activity. Due to its progestogenic activity, MPA decreases the body's release of gonadotropins and can suppress sex hormone levels. It works as a form of birth control by preventing ovulation.

Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking the androgen receptor (AR) and/or inhibiting or suppressing androgen production. They can be thought of as the functional opposites of AR agonists, for instance androgens and anabolic steroids (AAS) like testosterone, DHT, and nandrolone and selective androgen receptor modulators (SARMs) like enobosarm. Antiandrogens are one of three types of sex hormone antagonists, the others being antiestrogens and antiprogestogens.

Antiandrogens are used to treat an assortment of androgen-dependent conditions. In men, antiandrogens are used in the treatment of prostate cancer, enlarged prostate, scalp hair loss, overly high sex drive, unusual and problematic sexual urges, and early puberty. In women, antiandrogens are used to treat acne, seborrhea, excessive hair growth, scalp hair loss, and high androgen levels, such as those that occur in polycystic ovary syndrome (PCOS). Antiandrogens are also used as a component of feminizing hormone therapy for transgender women and as puberty blockers in transgender girls.

Sexology is the scientific study of human sexuality, including human sexual interests, behaviors, and functions. The term sexology does not generally refer to the non-scientific study of sexuality, such as social criticism.

Sexologists apply tools from several academic fields, such as anthropology, biology, medicine, psychology, epidemiology, sociology, and criminology. Topics of study include sexual development (puberty), sexual orientation, gender identity, sexual relationships, sexual activities, paraphilias, and atypical sexual interests. It also includes the study of sexuality across the lifespan, including child sexuality, puberty, adolescent sexuality, and sexuality among the elderly. The field of sexology also encompasses the study of sexuality among individuals with mental or physical disabilities. The sexological study of sexual dysfunctions and disorders, including erectile dysfunction and anorgasmia, are also mainstays.

Erotic asphyxiation (variously called asphyxiophilia, hypoxyphilia or breath control play) is the intentional restriction of oxygen to the brain for the purposes of sexual arousal. With a partner (or alone), the act often involves strangulation. The term autoerotic asphyxiation is used when the act is done by a person to themself. Colloquially, a person engaging in the activity is sometimes called a gasper. Erotic asphyxiation can lead to accidental death due to asphyxia.

The erotic interest in asphyxiation is classified as a paraphilia in the Diagnostic and Statistical Manual of the American Psychiatric Association.