Polymorphism of the promoter region of the serotonin 5-HT2C receptor gene and clozapine-induced weight gain

Objective: Weight gain, leading to further morbidity and poor treatment adherence, is a common consequence of treatment with antipsychotic drugs. A recent study showed that a polymorphism of the promoter region of the serotonin 5-HT2C receptor gene is associated with antipsychotic-induced weight gain. The authors determined whether this association held true for weight gain after clozapine treatment. Method: Thirty-two Chinese Han patients with first-episode schizophrenia were genotyped for the -759C/T polymorphism and had weight changes monitored after 6 weeks of clozapine treatment. Results: The authors found that the 10 patients with the -759T variant allele showed significantly less weight gain than those without this allele. The effect was strongest in the male patients and not apparent in the female patients. Conclusions: These findings identify an important genetic factor associated with clozapine-induced weight increases in schizophrenia.