The secondary aim of the study is to assess the safety and efficacy of the combination of quetiapine XR and SSRIs in patients with the diagnosis of PsyD. Metabolic factors including fasting glucose, fasting insulin, and fasting lipids (total cholesterol, HDL, LDL, and triglycerides) will be obtained at screen and at the 8-week endpoint of the study to assess the impact of treatment on the development of risk factors for metabolic syndrome. Measures of cognitive function (MGH Cognitive and Physical Functioning Questionnaire and RBANS) (Fava et al. 2006; Randolph et al. 1998) will be obtained at screen and the 8-week endpoint of the study to assess the impact of treatment on cognitive function.