Validating schizotypal personality disorders: problems with the schizophrenia connection.

The author questions the assumption that family relationship should be given primacy as the validating criterion in establishing diagnostic items for the DSM-III definition of schizotypal personality disorder (SPD). The presenting characteristics of clinically defined patients may be quite different from those that best describe the nonpatient relatives of schizophrenic patients encountered in genetic or high-risk studies. Since the DSM-III nomenclature is meant primarily for use in clinical settings, it must be based on symptom characteristics found in patients, not in nonpatient relatives. If the DSM-III SPD definitions are not optimal for genetic and high-risk studies, special criteria sets will be necessary for such research.