Schizotypal personality disorder is a psychiatric condition in which a person has difficulty with interpersonal relationships and disturbances in thought patterns, appearance, and behavior.

The cause is unknown. Genes are thought to be involved, because there is an increased incidence of this condition in relatives of schizophrenics.

However, schizotypal personality disorder should not be confused with schizophrenia. People with schizotypal personality disorder tend to have odd beliefs and behaviors, but they are not disconnected from reality and usually do not hallucinate. Hallucinations, delusions, and complete unawareness of reality are hallmarks of untreated or unsuccessfully treated schizophrenia.

Between 30% and 50% of people with schizotypal personality disorder also have a major depressive disorder. A second personality disorder, such as paranoid personality disorder, is also common with this condition.

People with schizotypal personality disorder may be severely disturbed. Their odd behavior may resemble that of people with schizophrenia. For example, they may also have unusual preoccupations and fears, such as fears of being monitored by government agencies.

More commonly, however, people with schizotypal personality disorder behave oddly and have unusual beliefs (aliens, witchcraft, etc.). They cling to these beliefs so strongly that it isolates them from normal relationships.

Full-blown hallucinations are unusual. However, people with schizotypal personality disorder are upset by their difficulty in forming and maintaining close relationships.

Some of the common signs of schizotypal personality disorder include the following:

• Discomfort in social situations
• Odd beliefs, fantasies, or preoccupations
• Odd behavior or appearance
• Odd speech
• No close friends
• Inappropriate displays of feelings

Some people may be helped by antipsychotic medications, but in many cases talk therapy is preferred.

Schizotypal personality disorder is usually a long-term (chronic) illness. The outcome of treatment varies based on the severity of the disorder.

• Poor social skills
• Lack of interpersonal relationships

Talk to your health care provider or mental health professional if:

• You have trouble forming and keeping relationships due to unusual beliefs
• You suspect that your child may have this problem

There is no known prevention. Awareness of risk, such as a family history of schizophrenia, may allow early diagnosis.

Moore DP, Jefferson JW. Schizotypal personality disorder. In: Moore DP, Jefferson JW, eds. Handbook of Medical Psychiatry. 2nd ed. Philadelphia, Pa: Mosby Elsevier; 2004: chap 136.