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.

The prevalence of frotteurism is unknown. The DSM estimates that 10%–14% of men seen in clinical settings for paraphilias or hypersexuality have frotteuristic disorder, indicating that the population prevalence is lower. However, frotteuristic acts, as opposed to frotteuristic disorder, may occur in up to 30% of men in the general population. The majority of frotteurs are male and the majority of victims are female, although female on male, female on female, and male on male frotteurs exist. This activity is often done in circumstances where the victim cannot easily respond, in a public place such as a crowded train or concert.

Usually, such nonconsensual sexual contact is viewed as a criminal offense: a form of sexual assault albeit often classified as a misdemeanor with minor legal penalties. Conviction may result in a sentence or psychiatric treatment.

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.

Frotteurism is a paraphilic interest in rubbing, usually one's pelvic area or erect penis, against a non-consenting person for sexual pleasure. It may involve touching any part of the body, including the genital area. A person who practices frotteuristic acts is known as a "frotteur". Toucherism is sexual arousal based on grabbing or rubbing one's hands against an unexpecting (and non-consenting) person. It usually involves touching breasts, buttocks or genital areas, often while quickly walking across the victim's path. Some psychologists consider toucherism a manifestation of frotteurism, while others distinguish the two. In clinical medicine, treatment of frotteuristic disorder involves cognitive behavior therapy coupled with the administration of a SSRI.

According to the "courtship disorder hypothesis", there is a species-typical courtship process in humans consisting of four phases. These phases are: "(1) looking for and appraising potential sexual partners; (2) pretactile interaction with those partners, such as by smiling at and talking to them; (3) tactile interaction with them, such as by embracing or petting; (4) and then sexual intercourse."

The associations between these phases and these paraphilias were first outlined by Kurt Freund, the originator of the theory: A disturbance of the search phase of courtship manifests as voyeurism, a disturbance of the pretactile interaction phase manifests as exhibitionism or telephone scatologia, a disturbance of the tactile interaction phase manifests as toucheurism or frotteurism, and the absence of the courtship behavior phases manifests as paraphilic rape (i.e., biastophilia). According to Freund, these paraphilias "can be conceptualized as a preference for a pattern of behavior or erotic fantasy in which one of these four phases of sexual interaction is intensified and distorted to such an extent that it appears to be a caricature of the normal, while the remaining phases are either omitted entirely or are retained only in a vestigial way."

Freund noted that "troilism" (a paraphilia for observing one’s sexual/romantic partner sexually interacting with a third party, usually unbeknownst to the third party) might also be a courtship disorder, troilism being a variant of voyeurism.

Appropriate behaviors depend on the social and cultural context, including time and place. Some behaviors that are unacceptable under most circumstances, such as public nudity or sexual contact between dancers, may be accepted or even encouraged during celebrations like Carnival or Mardi Gras. Where such cultural festivals alter normative courtship behaviors, the signs of courtship disorder may be masked or altered.

With paraphilic coercive disorder, the individual employs enough force to subdue a victim, but with sexual sadism disorder, the individual often continues to inflict harm regardless of the compliance of the victim, which sometimes escalates not only to the death of the victim, but also to the mutilation of the body. What is experienced by the sadist as sexual does not always appear obviously sexual to non-sadists: Sadistic rapes do not necessarily include penile penetration of the victim. In a survey of offenses, 77% of cases included sexual bondage, 73% included anal rape, 60% included blunt force trauma, 57% included vaginal rape, and 40% included penetration of the victim by a foreign object. Moreover, in 40% of cases, the offender kept a personal item of the victim as a souvenir.

On personality testing, sadistic rapists apprehended by law enforcement have shown elevated traits of impulsivity, hypersexuality, callousness, and psychopathy.

Although there appears to be a continuum of severity from mild ("hyperdominance" or "BDSM") to moderate ("paraphilic coercive disorder") to severe ('sexual sadism disorder), it is not clear if they are genuinely related or only appear related superficially.

Very little is known about how sexual sadism disorder develops. Most of the people diagnosed with sexual sadism disorder come to the attention of authorities by committing sexually motivated crimes. Surveys have also been conducted including people who are interested in only mild and consensual forms of sexual pain/humiliation (BDSM).

Most of the people with full-blown sexual sadism disorder are male, whereas the sex ratio of people interested in BDSM is closer to 2:1 male-to-female.

People with sexual sadism disorder" are at an elevated likelihood of having other paraphilic sexual interests.

Biastophilia (from Greek "biastes", "rape" + "-philia") and its Latin language-derived counterpart raptophilia (from Latin "rapere", "to seize"), also paraphilic rape, is a paraphilia in which sexual arousal is dependent on, or is responsive to, the act of assaulting an unconsenting person, especially a stranger. Some dictionaries consider the terms synonymous, while others distinguish raptophilia as the paraphilia in which sexual arousal is responsive to actually raping the victim.

The source of the arousal in these paraphilias is the victim's terrified resistance to the assault, and in this respect it is considered to be a form of sexual sadism. Biastophilia is accepted as potentially lethal, other such paraphilias including, but not being limited to asphyxiophilia, autassassinophilia, hybristophilia, and chremastistophilia.

Under the name paraphilic coercive disorder, this diagnosis was proposed for inclusion in DSM-5. This diagnosis, under the name "paraphilic rapism", was proposed and rejected in the DSM-III-R. It has been criticized because of the impossibility of reliably distinguishing between paraphilic rapists and non-paraphilic rapists, and because this diagnosis, under the term "Paraphilia NOS" (not otherwise specified), non-consent had been used in Sexually Violent Person/Predator commitment.

Czech sexology standardly use a concept of pathologic sexual aggressivity instead. This term is strongly distinguished from sadism. This disorder is understood as a coordination anomaly of the sexual motivation system (SMS), a "courtship disorder" according to Kurt Freund or displacement paraphilia by John Money, or a missing segment of SMS.

Historically, masochism has been associated with feminine submissiveness. This disorder became politically controversial when associated with domestic violence which was considered to be mostly caused by males. However a number of studies suggest that the disorder is common. In spite of its exclusion from DSM-IV in 1994, it continues to enjoy widespread currency amongst clinicians as a construct that explains a great many facets of human behaviour.

Sexual masochism that "causes clinically significant distress or impairment in social, occupational, or other important areas of functioning" is still in DSM-IV.

Child abuse and neglect consistently show up as risk factors to the development of personality disorders in adulthood. A study looked at retrospective reports of abuse of participants that had demonstrated psychopathology throughout their life and were later found to have past experience with abuse. In a study of 793 mothers and children, researchers asked mothers if they had screamed at their children, and told them that they did not love them or threatened to send them away. Children who had experienced such verbal abuse were three times as likely as other children (who did not experience such verbal abuse) to have borderline, narcissistic, obsessive-compulsive or paranoid personality disorders in adulthood. The sexually abused group demonstrated the most consistently elevated patterns of psychopathology. Officially verified physical abuse showed an extremely strong correlation with the development of antisocial and impulsive behavior. On the other hand, cases of abuse of the neglectful type that created childhood pathology were found to be subject to partial remission in adulthood.

Socioeconomic status has also been looked at as a potential cause for personality disorders. There is a strong association with low parental/neighborhood socioeconomic status and personality disorder symptoms. In a recent study comparing parental socioeconomic status and a child's personality, it was seen that children who were from higher socioeconomic backgrounds were more altuistic, less risk seeking, and had overall higher IQs. These traits correlate with a low risk of developing personality disorders later on in life. In a study looking at female children who were detained for disciplinary actions found that psychological problems were most negatively associated with socioeconomic problems. Furthermore, social disorganization was found to be inversely correlated with personality disorder symptoms.

Theodore Millon has proposed four subtypes of masochist. Any individual masochist may fit into none, one or more of the following subtypes:

In the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5), recurrent, intense sexual interest in corpses can be diagnosed under Other Specified Paraphilic Disorder (necrophilia) when it causes marked distress or impairment in important areas of functioning. A ten-tier classification of necrophilia exists:

1. Role players: People who get aroused from pretending their live partner is dead during sexual activity.

2. Romantic necrophiliacs: Bereaved people who remain attached to their dead lover's body.

3. Necrophilic fantasizers: People who fantasize about necrophilia, but never actually have sex with a corpse.

4. Tactile necrophiliacs: People who are aroused by touching or stroking a corpse, without engaging in intercourse.

5. Fetishistic necrophiliacs: People who remove objects (e.g., panties or a tampon) or body parts (e.g., a finger or genitalia) from a corpse for sexual purposes, without engaging in intercourse.

6. Necromutilomaniacs: People who derive pleasure from mutilating a corpse while masturbating, without engaging in intercourse.

7. Opportunistic necrophiliacs: People who normally have no interest in necrophilia, but take the opportunity when it arises.

8. Regular necrophiliacs: People who preferentially have intercourse with the dead.

9. Homicidal necrophiliacs: Necrosadists, people who commit murder in order to have sex with the victim.

10. Exclusive necrophiliacs: People who have an exclusive interest in sex with the dead, and cannot perform at all for living partners.

Sadistic personality disorder has been found to occur frequently in unison with other personality disorders. Studies have also found that sadistic personality disorder is the personality disorder with the highest level of comorbidity to other types of psychopathological disorders. In contrast, sadism has also been found in patients who do not display any or other forms of psychopathic disorders. One personality disorder that is often found to occur alongside sadistic personality disorder is conduct disorder, not an adult disorder but one of childhood and adolescence. Studies have found other types of illnesses, such as alcoholism, to have a high rate of comorbidity with sadistic personality disorder.

Researchers have had some level of difficulty distinguishing sadistic personality disorder from other forms of personality disorders due to its high level of comorbidity with other disorders.

Necrophilia is often assumed to be rare, but no data for its prevalence in the general population exists. Some necrophiles only fantasize about the act, without carrying it out. In 1958, Klaf and Brown commented that, although rarely described, necrophiliac fantasies may occur more often than is generally supposed.

Rosman and Resnick (1989) reviewed 122 cases of necrophilia. The sample was divided into genuine necrophiles, who had a persistent attraction to corpses, and pseudo-necrophiles, who acted out of opportunity, sadism, or transient interest. Of the total, 92% were male and 8% were female. 57% of the genuine necrophiles had occupational access to corpses, with morgue attendant, hospital orderly, and cemetery employee being the most common jobs. The researchers theorized that either of the following situations could be antecedents to necrophilia:

1. The necrophile develops poor self-esteem, perhaps due in part to a significant loss;

- (a) They are very fearful of rejection by others and they desire a sexual partner who is incapable of rejecting them; and/or

- (b) They are fearful of the dead, and transform their fear—by means of reaction formation—into a desire.

2. They develop an exciting fantasy of sex with a corpse, sometimes after exposure to a corpse.

The authors reported that, of their sample of genuine necrophiles:

- 68% were motivated by a desire for an unresisting and unrejecting partner;

- 21% by a want for reunion with a lost partner;

- 15% by sexual attraction to dead people;

- 15% by a desire for comfort or to overcome feelings of isolation; and

- 12% by a desire to remedy low self-esteem by expressing power over a corpse.

IQ data was limited, but not abnormally low. About half of the sample had a personality disorder, and 11% of true necrophiles were psychotic. Rosman and Resnick concluded that their data challenged the conventional view of necrophiles as generally psychotic, mentally deficient, or unable to obtain a consenting partner.

Sadistic personality disorder is a personality disorder involving which appeared in an appendix of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-III-R). The later versions of the DSM (DSM-IV, DSM-IV-TR and DSM-5) do not include it.

The words "sadism" and "sadist" are derived from Marquis de Sade.

Another theory suggests a possible relationship between histrionic personality disorder and antisocial personality disorder. Research has found 2/3 of patients diagnosed with histrionic personality disorder also meet criteria similar to those of the antisocial personality disorder, which suggests both disorders based towards sex-type expressions may have the same underlying cause. Women are hypersexualized in the media consistently, ingraining thoughts that the only way women are to get attention is by exploiting themselves, and when seductiveness isn't enough, theatricals are the next step in achieving attention. Men can just as well be flirtatious towards multiple women yet feel no empathy or sense of compassion towards them. They may also become the center of attention by exhibiting the "Don Juan" macho figure as a role-play.

Some family history studies have found that histrionic personality disorder, as well as borderline and antisocial personality disorders, tend to run in families, but it is unclear if this is due to genetic or environmental factors. Both examples suggest that predisposition could be a factor as to why certain people are diagnosed with histrionic personality disorder, however little is known about whether or not the disorder is influenced by any biological compound or is genetically inheritable. Little research has been conducted to determine the biological sources, if any, of this disorder.

In factitious disorder imposed on self, the affected person exaggerates or creates symptoms of illnesses in themselves to gain examination, treatment, attention, sympathy, and/or comfort from medical personnel. In some extreme cases, people suffering from Munchausen syndrome are highly knowledgeable about the practice of medicine and are able to produce symptoms that result in lengthy and costly medical analysis, prolonged hospital stays, and unnecessary operations. The role of "patient" is a familiar and comforting one, and it fills a psychological need in people with this syndrome. This disorder is distinct from hypochondriasis and other somatoform disorders in that those with the latter do not intentionally produce their somatic symptoms. Munchausen syndrome is distinct from other psychiatric disorders such as malingering in that Munchausen does not fabricate symptoms for material gain such as financial compensation, absence from work, or access to drugs.

Risk factors for developing factitious disorder include childhood traumas, growing up with parents/caretakers who were emotionally unavailable due to illness or emotional problems, a serious illness as a child, failed aspirations to work in the medical field, personality disorders, and low self-esteem. Factitious disorder is more common in men and is seen in young or middle-aged adults. Those with a history of working in healthcare are also at greater risk of developing it.

Arrhythmogenic Munchausen syndrome describes individuals who simulate or stimulate cardiac arrhythmias to gain medical attention.

A similar behavior called factitious disorder imposed on another has been documented in the parent or guardian of a child. The adult ensures that his or her child will experience some medical affliction, therefore compelling the child to suffer through treatments and spend a significant portion of their youth in hospitals. Furthermore, a disease may actually be initiated in the child by the parent or guardian. This condition is considered distinct from Munchausen syndrome. There is growing consensus in the pediatric community that this disorder should be renamed "medical abuse" to highlight the harm caused by the deception and to make it less likely that a perpetrator can use a psychiatric defense when harm is done.

Because there is uncertainty in treating suspected factitious disorder imposed on self, some advocate that health care providers first explicitly rule out the possibility that the person has another early-stage disease. Then they may take a careful history and seek medical records to look for early deprivation, childhood abuse, or mental illness. If a person is at risk to themself, psychiatric hospitalization may be initiated.

Healthcare providers may consider working with mental health specialists to help treat the underlying mood or disorder as well as to avoid countertransference. Therapeutic and medical treatment may center on the underlying psychiatric disorder: a mood disorder, an anxiety disorder, or borderline personality disorder. The patient's prognosis depends upon the category under which the underlying disorder falls; depression and anxiety, for example, generally respond well to medication and/or cognitive behavioral therapy, whereas borderline personality disorder, like all personality disorders, is presumed to be pervasive and more stable over time, and thus offers a worse prognosis.

People affected may have multiple scars on their abdomen due to repeated "emergency" operations.

Psychoanalytic theories incriminate authoritarian or distant attitudes by one (mainly the mother) or both parents, along with conditional love based on expectations the child can never fully meet. Using psychoanalysis, Freud believed that lustfulness was a projection of the patient's lack of ability to love unconditionally and develop cognitively to maturity, and that such patients were overall emotionally shallow.

He believed the reason for being unable to love could have resulted from a traumatic experience, such as the death of a close relative during childhood or divorce of one's parents, which gave the wrong impression of committed relationships. Exposure to one or multiple traumatic occurrences of a close friend or family member's leaving (via abandonment or mortality) would make the person unable to form true and affectionate attachments towards other people.

Empirical studies have found that the prognosis for conversion disorder varies widely, with some cases resolving in weeks, and others enduring for years or decades. There is also evidence that there is no cure for Conversion Disorder, and that although patients may go into remission, they can relapse at any point. Furthermore, many patients who are 'cured' continue to have some degree of symptoms indefinitely.

Information on the frequency of conversion disorder in the West is limited, in part due to the complexities of the diagnostic process. In neurology clinics, the reported prevalence of unexplained symptoms among new patients is very high (between 30 and 60%). However, diagnosis of conversion typically requires an additional psychiatric evaluation, and since few patients will see a psychiatrist it is unclear what proportion of the unexplained symptoms are actually due to conversion. Large scale psychiatric registers in the US and Iceland found incidence rates of 22 and 11 newly diagnosed cases per 100,000 person-years, respectively. Some estimates claim that in the general population, between 0.011% and 0.5% of the population have conversion disorder.

There are many possible causes for this disorder. One such possibility is an underlying personality disorder. Individuals with FD may be trying to repeat a satisfying childhood relationship with a doctor. Perhaps also an individual has a desire to deceive or test authority figures. The underlying desire to resume the role of a patient and be cared for can also be considered an underlying personality disorder. Abuse, neglect, or abandonment during childhood are also probable causes.

These individuals may be trying to reenact unresolved issues with their parents. A history of frequent illnesses may also contribute to the development of this disorder. In some cases, individuals afflicted with FD are accustomed to actually being sick, and thus return to their previous state to recapture what they once considered the 'norm.' Another cause is a history of close contact with someone (a friend or family member) who had a severe or chronic condition. The patients found themselves subconsciously envious of the attention said relation received, and felt that they themselves faded into the background. Thus medical attention makes them feel glamorous and special.

Some individuals experience only a few outbreaks of the disorder. However, in most cases, factitious disorder is a chronic and long-term condition that is difficult to treat. There are relatively few positive outcomes for this disorder; in fact, treatment provided a lower percentage of positive outcomes than did treatment of individuals with obvious psychotic symptoms such as people with schizophrenia. In addition, many individuals with factitious disorder do not present for treatment, often insisting their symptoms are genuine. Some degree of recovery, however, is possible. The passage of time seems to help the disorder greatly. There are many possible explanations for this occurrence, although none are currently considered definitive. It may be that an FD individual has mastered the art of feigning sickness over so many years of practice that the disorder can no longer be discerned. Another hypothesis is that many times an FD individual is placed in a home, or experiences health issues that are not self-induced or feigned. In this way, the problem with obtaining the 'patient' status is resolved because symptoms arise without any effort on the part of the individual.

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).

Data from the 2001–02 National Epidemiologic Survey on Alcohol and Related Conditions indicates a prevalence rate of 2.36% in the American general population. It appears to occur with equal frequency in males and females. In one study, it was seen in 14.7% of psychiatric outpatients.