Severe weight gain and glucose dysregulation are serious problems in patients treated with second-generation ('atypical') antipsychotics (SGA). These side effects frequently interfere with medication compliance and necessitate discontinuation of treatment. Although the causal mechanisms for weight and glucose dysregulation are not well understood, one promising area of investigation targets SGA-induced disturbances in appetite and in appetite-regulating hormones. Findings from our group (and others) demonstrate SGA treatment-related increases in fasting levels of the appetite-stimulating hormone, ghrelin, as well as increases in self-report hunger. This novel study will examine prospective changes in ghrelin and in the 'satiety-signaling' peptide YY (PYY) as measured before and after participants consume a standard mixed-macronutrient meal. Data are obtained at baseline (within 4 weeks of beginning medication), and again 2 months and 4 months later.