Obesity has taken an epidemic proportion since the 1980s all around the world. It leads to metabolic complications and reduces lifespan. The psychiatric population, in particular those treated with certain psychotropic drugs, has been shown to have higher rates of obesity than the general population. CREB-regulated transcription coactivator 1 (CRTC1), CREB-regulated transcription coactivator 2 (CRTC2) and 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1) polymorphisms have shown significant association with obesity and type 2 diabetes in psychiatric patients receiving psychotropics (previous studies done at the UPPC). Exploring pharmacogenetics, regarding influence of polymorphisms on gene expression, may lead to a better understanding of obesity pathogenesis.However, influence of CRTC1, CRTC2 and HSD11B1 polymorphisms on gene expression is unknown.