Objective: Schizotypal personality disorder (SPD) has many phenomenological, genetic, physiologic, and neuroanatomical commonalities with schizophrenia. Patients with the disorder often suffer from marked social and occupational impairment, yet they have been difficult to treat with medications because of their unusual sensitivity to side effects. This study was designed to determine whether low-dose risperidone treatment is acceptable to SPD patients and can reduce characteristic schizotypal symptoms. In addition, if SPD patients respond to an antipsychotic medication, this will provide support for the notion of a commonality in treatment response between SPD and schizophrenia.
Method: Twenty-five patients with DSM-IV-defined SPD were entered into a 9-week randomized, double-blind, placebo-controlled study of low-dose risperidone (starting dose of 0.25 mg/day, titrated upward to 2 mg/day) in the treatment of SPD. Patients were rated with the Positive and Negative Syndrome Scale (PANSS), the Schizotypal Personality Disorder Questionnaire, the Hamilton Rating Scale for Depression, and the Clinical Global Impressions scale. Data were collected from 1995 to 2001.
Results: The subjects had a low incidence of depression and of comorbid borderline personality disorder. Patients receiving active medication had significantly (p <.05) lower scores on the PANSS negative and general symptom scales by week 3 and on the PANSS positive symptom scale by week 7 compared with patients receiving placebo. Side effects were generally well tolerated, and there was no group difference in dropout rate for side effects.
Conclusion: Low-dose risperidone appears to be effective in reducing symptom severity in SPD and is generally well tolerated.