Prefrontal sulcal prominence is inversely related to response to clozapine in schizophrenia

The object of this study was to determine if brain computed tomography (CT) scan measures are related to treatment response to clozapine, an atypical antipsychotic drug that is effective in some therapy-resistant schizophrenic patients. Thirty-four therapy-resistant patients were evaluated with the Brief Psychiatric Rating Scale (BPRS) before and after 6 weeks of treatment with clozapine. The patients were classified into Nonresponders, Moderate Responders, and Good Responders based on the percent change in BPRS. Comparison of these groups on prefrontal sulcal prominence (PSP) indicated a statistically significant linear trend, with nonresponders having the highest, moderate responders an intermediate degree, and good responders the least PSP. There were no linear trends for the ventricular-brain ratio (VBR), and no quadratic trends for either brain measure. A similar linear trend relating PSP to four of five BPRS subscales, including both positive and negative symptoms, was observed. The relationship between PSP and treatment response was also assessed with multiple linear regression, and PSP significantly contributed to prediction of BPRS at 6 weeks. The results are discussed with regards to the hypothesis that the effect of clozapine on psychopathology depends on prefrontal cortical function.