Letter to the Editors

Diurnal variation in plasma homovanillic acid in patients with schizophrenia and healthy controls

It has been suggested that the family history of psychotic disorders is useful in defining homogeneous groups of bipolar patients. The plasma homovanillic acid (pHVA) concentrations have been related to the effect of antipsychotic treatment in psychotic patients. We have studied the influence of a positive family history of psychotic disorders both on the variation of pHVA levels and on the relation between pHVA concentrations and the clinical response to treatment. Clinical status and pHVA levels were assessed in 58 medication free patients before and after 4 weeks of treatment with olanzapine and lithium. Clinical improvement correlated positively with pHVA levels on the 28th day of treatment only in the patients having first degree relatives with psychotic disorders. The pHVA levels did not decrease after 28 days of treatment. Our results reinforce the idea that a positive family history of psychosis in psychotic bipolar disorders may constitute a good basis for sub-grouping these patients.

Although several studies have identified abnormal rates of neurological soft signs (NSS) as a manifestation of CNS dysfunction in schizophrenia, differences in sample populations have contributed to a discrepancy in empirical findings. Furthermore, little is known about the potential of NSS to predict a clinical response to antipsychotic medications. The present study tests the associations between NSS and schizophrenia symptomatology and examines NSS as a potential marker for predicting treatment response.

Nineteen unmedicated male schizophrenia patients were treated prospectively with haloperidol for six weeks. The subjects were assessed for pre and post-treatment NSS and schizophrenia symptomatology (Brief Psychiatric Rating Scale, BPRS).

NSS at baseline were significantly associated with baseline symptoms on the Positive, Negative, and Psychological Discomfort BPRS subscales. NSS showed a strong trend toward improvement during six weeks of a prospective haloperidol trial. Hierarchal linear regression analyses indicated that more severe baseline NSS predicted poorer response to haloperidol treatment as measured by post-treatment BPRS Total subscale scores.

NSS at untreated baseline are associated with baseline symptom severity, and elevated NSS are predictive of a smaller degree of improvement in symptoms after antipsychotic treatment. These findings are consistent with the hypothesis that NSS are linked to the neuropathology that underlies schizophrenia symptomatology and course.