The specific psychiatric diagnoses anticipated in the subject pool include the conditions that lithium and sertraline are indicated to treat, including Bipolar Affective Disorders, Cyclothymic Disorder, Schizoaffective Disorder, Major Depressive Disorder, Dysthymic Disorder, Obsessive-Compulsive Disorder, Panic Disorder, Posttraumatic Stress Disorder, Premenstrual Dysphoric Disorder, and Social Anxiety Disorder.