Effects of medication history on midlatency auditory evoked responses in schizophrenia

• Published in: Schizophrenia research Vol. 11; no. 3; pp. 251 - 258
• Main Authors: Erwin, Roland J., Shtasel, Derri, Gur, Raquel E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.1994; Elsevier Science
• Subjects: Adolescent; Adult; Adult and adolescent clinical studies; Antipsychotic Agents - adverse effects; Antipsychotic Agents - therapeutic use; Biological and medical sciences; Cerebral Cortex - drug effects; Cerebral Cortex - physiopathology; Evoked potential; Evoked Potentials, Auditory - drug effects; Evoked Potentials, Auditory - physiology; Female; Humans; Male; Medical sciences; P50; Psychiatric Status Rating Scales; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Reaction Time - drug effects; Reaction Time - physiology; Recovery cycle; Reference Values; Schizophrenia; Schizophrenia - drug therapy; Schizophrenia - physiopathology; Schizophrenia, Paranoid - drug therapy; Schizophrenia, Paranoid - physiopathology; Schizophrenia, Paranoid - psychology; Schizophrenic Psychology; Sensory gating; Schizophrenia; P1; Recovery cycle; P50; Sensory gating; Evoked potential; Human; Psychosis; Chemotherapy; Treatment; Neuroleptic; Psychotropic; Auditory evoked potential; Information processing; Electrophysiology; Antecedent
• ISSN: 0920-9964; 1573-2509
• DOI: 10.1016/0920-9964(94)90019-1

The recovery cycle of the P1 component of the auditory evoked potential (50–70 ms latency) has been reported as abnormal in both unmedicated and medicated patients with schizophrenia when a paired stimuli protocol is used to examine recovery. However, findings have been mixed when a stimulus train protocol is used. This study examined the effects of medication history on P1 abnormalities in schizophrenia assessed by a stimulus train protocol. Auditory evoked potentials were recorded from 14 normal controls, 14 neuroleptic naive patients with schizophrenia and 14 previously medicated patients in response to binaural clicks presented at three stimulus rates: 1/s, 5/s and 10/s. Neuroleptic naive patients showed a smaller P1 at the baseline rate (1/s) and greater recovery (less amplitude suppression) at faster rates than did normal controls or previously medicated patients. Additional analyses suggested that this latter effect was not due to smaller baseline P1 amplitudes. Greater recovery in neuroleptic naive patients was not associated with clinical symptomatology contrary to previous findings of the authors for a mixed sample of neuroleptic naive and previously medicated patients. Medication status appears to account for some of the variability in P1 abnormalities in schizophrenia although identification of the underlying mechanism responsible requires further study.