SCHIZOTYPAL PERSONALITY-DISORDER .1. THE CLINICAL SYNDROME

This article reviews the major research in the area of schizotypal per sonality disorder since its appearance in the third edition of the Dia gnostic and Statistical Manual for Psychiatric Disorders, (American Ps ychiatric Association, 1987). Validation studies examining the diagnos tic sensitivity and specificity of schizotypal symptoms, as well as st udies examining its genetic relationship with schizophrenia, are revie wed. If the present prototypical classification system is to be mainta ined, then a refinement of the diagnostic criteria may be necessary in combination with a restructuring of the cluster A personality disorde rs. In addition, a differential weighting of the symptoms may increase the discriminant validity between schizotypal and borderline personal ity disorder. Establishment of diagnostic validity may benefit greatly by adopting a symptom-based approach in which the individual symptoms are examined instead of the entire syndrome. A symptom-based approach can also circumvent the problem of heterogeneity that emerges in most of the studies. Clearly, more work is needed using better defined pop ulations and focusing on the individual symptoms that best describe th e disorder.