Schizotypal personality disorder, or simply schizotypal disorder, is a personality disorder that is characterized by a need for social isolation, odd behavior and thinking, and often unconventional beliefs.
The schizotypal individual develops a fear of, strong objection to, or incapacity for social interaction, due to the sum of their past social experiences being negative in nature. As infants they do not learn how to interact with others, and as children and adults this inability quickly makes them a target for other people. Eventually, the individual learns (most often unconsciously) to see people as harmful and a source of negativity, suffering and ostracization. This leads to the development of "ideas of reference," in which the schizotypal individual believes that events are of special relevance to them or that benign events are somehow related to them (e.g., sees two people laughing and believes that the people are laughing at them). The individual may realize that their ideas of reference are irrational, but maintains them nonetheless. This exacerbates the individual's social anxiety, causing them to skew away from society and withdraw into their own world.
Although listed in the DSM-IV-TR on Axis II, schizotypal personality disorder is widely understood to be a "schizophrenia spectrum" disorder. If you look at the relatives of individuals who have been diagnosed with schizophrenia, rates of schizotypal PD will be much higher in those individuals than in the relatives of people with other mental illnesses or in the relatives of community controls with no mental illness. Technically speaking, schizotypal PD is an "extended phenotype" that helps geneticists track the familial or genetic transmission of the genes that are implicated in schizophrenia There are dozens of studies showing that individuals with schizotypal PD look similar to individuals with schizophrenia on a very wide range of neuropsychological tests. Cognitive deficits in patients with schizotypal PD are very similar to, but somewhat milder than, those for patients with schizophrenia.
Social / Environmental
People with schizotypal PD, like patients with schizophrenia, may be quite sensitive to interpersonal criticism and hostility, and there is now evidence to suggest that parenting styles, early separation and early childhood neglect can lead to the development of schizotypal traits
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