Weight gain appears to be a serious side effect encountered during treatment with many
antipsychotic drugs. Although the propensities of inducing
weight gain vary considerably between
antipsychotics,
weight gain is mostly observed in atypical
antipsychotics, increasingly prescribed for a variety of
psychiatric disorders. Beside the psychological consequences
weight gain may influence patients' compliance and secondary medical comorbidities related to being
overweight may arise, including diabetes, hypertonia, respiratory problems, and some types of
cancer.
Obesity research generally suggests that a complex system of
neurotransmitters,
neuropeptides,
hormones and immune related factors interact in neural circuits involving at least the hypothalamus, the solitary tract and cortical structures to regulate energy homeostasis and
body weight.
Antipsychotics that have
weight gain inducing properties may disrupt associated pathways at any of these levels, although it remains unclear what the mechanisms of action might be. Given the potential deleterious effects of
weight gain, individual predictors of
weight gain would be extremely helpful at the beginning of pharmacological treatment with atypical
antipsychotics, allowing
obesity to be avoided or for counteractive steps such as
dietary restrictions to be taken in predisposed individuals. So far, only a few predictors to detect individuals at high risk have been reported and these have limited power. It is likely that genetic factors play a major role in determining individual response to
antipsychotics as well as their side effect profile. In this article, we have reviewed literature related to
antipsychotic-induced
weight gain and have discussed the major issues, before updating the reader on current
obesity research findings. Finally, we emphasize previous studies relating to the pharmacogenetics of
antipsychotic-induced
weight gain.