Schizotypal personality disorder (StPD or SPD), also known as schizotypal disorder, is a cluster A personality disorder characterized by thought disorder, paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs as described by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Personality disorders that are classified as cluster A are grouped based on traits such as odd and eccentric behavior, which is contrary to cluster B and cluster C personality disorders, which are known for dramatic and anxious behavior. In the International Classification of Diseases, the latest edition of which is the ICD-11, schizotypal disorder is not classified as a personality disorder, but among psychotic disorders.
People with this disorder often 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. People with StPD may react oddly in conversations, such as not responding as expected, or talking to themselves. They frequently interpret situations as being strange or having unusual meanings for them; paranormal and superstitious beliefs are common. People with StPD 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.