Weight gain as a predictor of long term clozapine efficacy

The aim of this study was to evaluate weight gain during clozapine treatment and to determine the possible relationship between psychiatric improvement and weight gain. 15 treatment-resistant schizophrenic inpatients were assessed by rating scales [Brief Psychiatric Rating Scale (BPRS); Positive and Negative Symptoms Scores (PANSS)] for 21 months. Bodyweight was evaluated before inclusion and at each subsequent psychiatric assessment after the beginning of clozapine treatment. In the first period (the period between inclusion and the first minimal value of BPRS scores), all patients presented with a significant improvement in total BPRS and other rating scales, reaching at 10 months a 58% decrease from the initial value of BPRS. However, during the second period (the period after the first minimum), we clearly identified 2 patterns of evolution: in group 1, where patients experienced a marked improvement in schizophrenia symptoms followed by subsequent stability, a regular weight gain was observed; in contrast, no significant weight profile was noted in group 2 where:patients, after an initial response for 10 months, experienced clinical instability that required higher doses of clozapine. These results corroborate the clinically observed correlation between the long term antipsychotic efficacy of clozapine and weight gain.