Effect of Quetiapine on Sleep Architecture in Bipolar Depression and Major Depressive Disorder

Primary Objective: To assess the objective (polysomnographic) change in sleep quality before and after introduction of Seroquel (Quetiapine) in treatment of patients with Bipolar Depression or Major Depressive Disorder. Secondary Objectives: To assess the objective (polysomnographic) and subjective changes in sleep quality parameters before and at different stages after introduction of Seroquel (Quetiapine) treatment, longitudinally, and to correlate these changes with measures of illness severity. Study Design: Prospective polysomnographic (PSG) study of patients before and after treatment with Seroquel (Quetiapine). PSG recordings will be done three (optional four) times during the study: before starting the Seroquel (Quetiapine) (baseline), at day 2 to 4 (early) and day 21 to 28 (longer term). (Optional fourth PSG can be done at day 42-56). PSG will be completed at patients home with a portable PSG.