Response and side effects to psychotropic medications are significantly related to genetic factors. CAMH’s new Pharmacogenetics Research Clinic started in 2008 and is one of the first of its kind dedicated to understanding the genetics of patients’ response and side effect to psychiatric medication. Pharmacogenetic research provides an opportunity to leave behind the dark ages of prescribing by trial and error, and to move into a new era of precise, personalized prescription based on an individual genetic composition of each patient.