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.

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.

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.

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.

The person's appearance, behavior, and history, along with a psychological evaluation, are usually sufficient to establish a diagnosis. There is no test to confirm this diagnosis. Because the criteria are subjective, some people may be wrongly diagnosed.

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.

Diagnosing factitious disorder imposed on self requires a clinical assessment. Clinicians should be aware that those presenting with symptoms (or persons reporting for that person) may malinger, and caution should be taken to ensure there is evidence for a diagnosis. Lab tests may be required, including complete blood count (CBC), urine toxicology, drug levels from blood, cultures, coagulation tests, assays for thyroid function, or DNA typing. In some cases CT scan, magnetic resonance imaging, psychological testing, electroencephalography, or electrocardiography may also be employed. A summary of more common and reported cases of factitious disorder (Munchausen syndrome), and the laboratory tests used to differentiate these from authentic disease is provided below:

There are several symptoms that together point to factitious disorder, including frequent hospitalizations, knowledge of several illnesses, frequently requesting medication such as pain killers, openness to extensive surgery, few or no visitors during hospitalizations, and exaggerated or fabricated stories about several medical problems. Factitious disorder should not be confused with hypochondria, as people with factitious disorder syndrome do not really believe they are sick; they only want to be sick, and thus fabricate the symptoms of an illness. It is also not the same as pretending to be sick for personal benefit such as being excused from work or school.

People may fake their symptoms in multiple ways. Other than making up past medical histories and faking illnesses, people might inflict harm on themselves by consuming laxatives or other substances, self-inflicting injury to induce bleeding, and altering laboratory samples.” Many of these conditions do not have clearly observable or diagnostic symptoms and sometimes the syndrome will go undetected because patients will fabricate identities when visiting the hospital several times. Factitious disorder has several complications, as these people will go to great lengths to fake their illness. Severe health problems, serious injuries, loss of limbs or organs, and even death are possible complications.

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

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.

The previous edition of the Diagnostic and Statistical Manual of Mental Disorders, DSM IV-TR, defines histrionic personality disorder (in Cluster B) as:

The DSM-IV requires that a diagnosis for any specific personality disorder also satisfies a set of general personality disorder criteria.

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.

The psychological mechanism of conversion can be the most difficult aspect of a conversion diagnosis. Even if there is a clear antecedent trauma or other possible psychological trigger, it is still not clear exactly how this gives rise to the symptoms observed. Patients with medically unexplained neurological symptoms may not have any psychological stressor, hence the use of the term "functional neurological symptom disorder" in DSM-V as opposed to "conversion disorder", and DSM-V's removal of the need for a psychological trigger.

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.

The word '' means 'substitute'. It is coded in the DSM-IV under Factitious Disorder NOS (not otherwise specified). Münchausen by proxy is the involuntary use of another individual to play the patient role. For example, false symptoms are produced in children by the caregivers or parents, to produce the appearance of illness, or they may give misleading medical histories about their children. The parent may falsify the child's medical history or tamper with laboratory tests to make the child appear sick. Occasionally, in Münchausen by proxy, the caregiver actually injures the child or makes it sick to ensure that the child is treated. For instance, a father whose son is coeliac might knowingly introduce gluten into the diet. Such parents may be validated by the attention that they receive from having a sick child.

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.

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.

No true psychiatric medications are prescribed for factitious disorder. However, selective serotonin reuptake inhibitors (SSRIs) can help manage underlying problems. Medicines such as SSRIs that are used to treat mood disorders can be used to treat FD, as a mood disorder may be the underlying cause of FD. Some authors (such as Prior and Gordon 1997) also report good responses to antipsychotic drugs such as Pimozide. Family therapy can also help. In such therapy, families are helped to better understand patients (the individual in the family with FD) and that person's need for attention.

In this therapeutic setting, the family is urged not to condone or reward the FD individual's behavior. This form of treatment can be unsuccessful if the family is uncooperative or displays signs of denial and/or antisocial disorder. Psychotherapy is another method used to treat the disorder. These sessions should focus on the psychiatrist's establishing and maintaining a relationship with the patient. Such a relationship may help to contain symptoms of FD. Monitoring is also a form that may be indicated for the FD patient's own good; FD (especially proxy) can be detrimental to an individual's health—if they are, in fact, causing true physiological illnesses. Even faked illnesses/injuries can be dangerous, and might be monitored for fear that unnecessary surgery may subsequently be performed.

There is a considerable personality disorder diagnostic co-occurrence. Patients who meet the DSM-IV-TR diagnostic criteria for one personality disorder are likely to meet the diagnostic criteria for another. Diagnostic categories provide clear, vivid descriptions of discrete personality types but the personality structure of actual patients might be more accurately described by a constellation of maladaptive personality traits.

"Sites used DSM-III-R criterion sets. Data obtained for purposes of informing the development of the DSM-IV-TR personality disorder diagnostic criteria."

Abbreviations used: "PPD – Paranoid Personality Disorder, SzPD – Schizoid Personality Disorder, StPD – Schizotypal Personality Disorder, ASPD – Antisocial Personality Disorder, BPD – Borderline Personality Disorder, HPD – Histrionic Personality Disorder, NPD – Narcissistic Personality Disorder, AvPD – Avoidant Personality Disorder, DPD – Dependent Personality Disorder, OCPD – Obsessive-Compulsive Personality Disorder, PAPD – Passive-Aggressive Personality Disorder."

Currently, genetic research for the understanding of the development of personality disorders is severely lacking. However, there are a few possible risk factors currently in discovery. Researchers are currently looking into genetic mechanisms for traits such as aggression, fear and anxiety, which are associated with diagnosed individuals. More research is being conducted into disorder specific mechanisms.

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.

About 25-40% of youths diagnosed with conduct disorder qualify for a diagnosis of antisocial personality disorder when they reach adulthood. For those that do not develop ASPD, most still exhibit social dysfunction in adult life.

Conduct disorder is classified in the fourth edition of "Diagnostic and Statistical Manual of Mental Disorders" (DSM). It is diagnosed based on a prolonged pattern of antisocial behaviour such as serious violation of laws and social norms and rules in people younger than the age of 18. Similar criteria are used in those over the age of 18 for the diagnosis of antisocial personality disorder. No proposed revisions for the main criteria of conduct disorder exist in the "DSM-5"; there is a recommendation by the work group to add an additional specifier for callous and unemotional traits. According to DSM-5 criteria for conduct disorder, there are four categories that could be present in the child's behavior: aggression to people and animals, destruction of property, deceitfulness or theft, and serious violation of rules.

Almost all adolescents who have a substance use disorder have conduct disorder-like traits, but after successful treatment of the substance use disorder, about half of these adolescents no longer display conduct disorder-like symptoms. Therefore, it is important to exclude a substance-induced cause and instead address the substance use disorder prior to making a psychiatric diagnosis of conduct disorder.