Epidemiology and mechanisms of weight gain induced by psychotropic drugs

Weight gain occurs during treatment with drugs of different chemical structures and is an important problem, when patients are treated with antidepressants, antipsychotics, or mood stabilizers. The clinical relevance of drug-induced weight changes is due to increased endocrine and metabolic morbidity, changes in clinical laboratory parameters and reduced treatment compliance. Regarding the underlying mechanisms, the important role of neurotransmitter systems has been discussed since decades. However, recent studies on the effects of psychotropic agents on major immune-endocrine systems involved in appetite and weight regulation indicate that the fat-cell derived hormone leptin and inflammatory cytokine networks such as the tumor-necrosis-factor (TNF) system may play an additional important role. Activation of the TNF system is a sensitive and specific marker for the potential of psychotropic drugs to induce weight gain. But, immune-endocrine parameters do not reliable predict weight changes in individual patients. In contrast, weight gain very early during drug treatment significantly correlates to further weight development.