Pharmacogenetic Aspects of Antipsychotic Drug-induced Weight Gain - A Critical Review

Treatment with several antipsychotic drugs can result in weight gain, which may lead to further morbidity such as type 2 diabetes and cardiovascular disease via the development of metabolic syndrome. These important and problematic metabolic consequences of antipsychotic drug treatment probably reflect a pharmacological disruption of the mechanisms involved in control of food intake and body weight. The extent of weight gain following antipsychotic drug treatment shows substantial variability between individuals, due in part to genetic factors. Common functional polymorphisms in many candidate genes implicated in the control of body weight and various aspects of energy and lipid metabolism have been investigated for association with weight gain in subjects receiving antipsychotic drug treatment, and with metabolic pathology in chronic schizophrenia. Perhaps the strongest and most replicated findings are the associations with promoter polymorphisms in the 5-HT2C receptor and leptin genes, although many other possible genetic risk factors, including polymorphisms in the fat mass and obesity associated (FTO) gene and genes for the alpha2A adrenoceptor and melanocortin4 receptor, have been reported. Genome-wide association studies (GWAS) have also addressed antipsychotic-induced weight gain and other indicators of metabolic disturbances. However there is as yet little consistency between these studies or between GWAS and classical candidate gene approaches. Identifying common genetic factors associated with drug-induced weight gain and its metabolic consequences may provide opportunities for personalized medicine in the predictive assessment of metabolic risk as well as indicating underlying physiological mechanisms.