Schizotypal personality disorder (StPD or SPD), also known as schizotypal disorder, is a cluster A personality disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM) classification describes the disorder specifically as a personality disorder characterized by thought disorder, paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs. People with this disorder feel pronounced discomfort in forming and maintaining social connections with other people, primarily due to the belief that other people harbor negative thoughts and views about them. Peculiar speech mannerisms and socially unexpected modes of dress are also characteristic. Schizotypal people may react oddly in conversations, not respond, or talk to themselves. They frequently interpret situations as being strange or having unusual meanings for them; paranormal and superstitious beliefs are common. Schizotypal people usually disagree with the suggestion that their thoughts and behaviors are a 'disorder' and seek medical attention for depression or anxiety instead. Schizotypal personality disorder occurs in approximately 3% of the general population and is more commonly diagnosed in males.
History
StPD was introduced in 1980 in the DSM-III. Its inclusion provided a new classification for schizophrenia-spectrum disorders and of personality disorders that were previously unspecified. Its diagnosis was developed through differentiating the classifications of borderline personality disorder, of which some of the diagnosed population demonstrated schizophrenia-spectrum traits. When the separation of borderline personality disorder and StPD was originally suggested by Spitzer and Endicott, Siever and Gunderson opposed the distinction. Siever and Gunderson's opposition to Spitzer and Endicott was that StPD was related to schizophrenia. Spitzer and Endicott stated "We believe, as do the authors, that the evidence for the genetic relationship between Schizotypal features and Chronic Schizophrenia is suggestive rather than proven". StPD was included in the DSM-IV and the DSM-V and saw little change in its diagnosis.
Epidemiology
The reported prevalence of StPD in community studies ranges from 1.37% in a Norwegian sample, to 4.6% in an American sample. A large American study found a lifetime prevalence of 3.9%, with somewhat higher rates among men (4.2%) than women (3.7%). It may be uncommon in clinical populations, with reported rates of up to 1.9%. It has been estimated to be somewhere between 0% and 5.2% of the general population. Together with other cluster A personality disorders, it is also very common among homeless people who show up at drop-in centers, according to a 2008 New York study. The study did not address homeless people who do not show up at drop-in centers. Schizotypal disorder may be overdiagnosed in Russia and other post-Soviet states.
Prognosis
People with StPD usually had symptoms of schizotypal personality disorder in childhood. Traits of StPD usually remain consistently present over time, although can fluctuate greatly in severity and stability. DSM characterizes StPD as having nine major symptoms: ideas of reference, odd/magical beliefs, social anxiety, not having close friends, odd or eccentric behavior, odd speech, unusual perceptions, suspiciousness, schizoobsessive behaviors and constricted affect. There may be gender differences in the symptomology of men and women with StPD. Women with the disorder might be more likely to have less severe cognitive deficits, and more severe social anxiety and magical thinking. People with StPD are more likely to only have a high school education, to be unemployed, and to have significant functional impairment. The two traits of StPD which are least likely to change are paranoia and abnormal experiences.
Obsessive-compulsive disorder coexistence
People who are treatment resistant to obsessive–compulsive disorder behavioral therapy and medication that also display odd or eccentric behaviors could contribute to the coexistence of obsessive-compulsive disorder with schizotypal disorder.