SCHIZOPHRENICS WITH SMALL P300 - A SUBGROUP WITH A NEURODEVELOPMENTALDISTURBANCE AND A HIGH-RISK FOR TARDIVE-DYSKINESIA

Schizophrenics with a neurodevelopmental disturbance resulting in micr o- and macroanatomical cortical abnormalities are supposed to form a s ubgroup clinically characterized by low premorbid adjustment, early on set, incomplete remission, poor outcome, male predominance and high ri sk for tardive dyskinesia. A small amplitude of the event-related P3 ( P300) potential could be a marker of this subgroup, because the cortic al neurons and their orderly laminar arrangement are crucial for the e lectrogenesis of P3. In a 2-year follow-up study, auditory evoked P3 w as recorded in 89 stabilized schizophrenic outpatients. Patients who d eveloped tardive dyskinesia during the follow-up had smaller P3 than m atched controls. Furthermore, a small P3 was associated with low premo rbid adjustment, pronounced residual symptoms, low relapse rate, and m ale predominance. These findings indicate that schizophrenic patients with a reduced P3 have a higher risk of developing tardive dyskinesia and correspond clinically to a schizophrenic subgroup with a supposedl y neurodevelopmental disturbance.