Understanding Brain Reward Responses in Individuals With Major Depressive Disorder

Overall Inclusion Criteria: * Right-handed * Agrees to use an effective form of contraception throughout the study Inclusion Criteria for Depressed Participants: * Meets overall inclusion criteria * Meets DSM-IV diagnosis criteria for major depressive disorder * Score of at least 16 on the 21-item HAM-D scale Overall Exclusion Criteria: * Left-handed or ambidextrous * Claustrophobic * Neurological or medical illness (e.g., attention deficit hyperactivity disorder, head injury, loss of consciousness, seizures) * Pregnant Exclusion Criteria for Depressed Participants: * Meets any of the overall exclusion criteria * Has been treated with electroconvulsive therapy within 6 months of study entry * Has taken any benzodiazepine medications for at least 2 weeks prior to study entry and discontinued use of the medication for reasons other than participating in the study * Has taken any dopaminergic medications (including methylphenidate) or neuroleptics for at least 6 months prior to study entry and discontinued use of the medication for reasons other than participating in the study * Has taken any fluoxetine medications for at least 6 weeks prior to study entry and discontinued use of the medication for reasons other than participating in the study * Has taken any medications that may have antidepressant properties (including some herbal supplements) within 2 weeks of study entry * Has taken any medications that may affect blood flow (including some blood pressure medications) within 2 weeks of study entry * Current or past history of MDD with psychotic features * Meets DSM-IV diagnosis criteria for organic mental disorder; substance use disorder (within 1 year of study entry); lifetime substance dependence; schizophrenia; delusional disorder; bipolar disorder; post-traumatic stress disorder; eating disorder; acute bereavement; severe borderline or antisocial personality disorder; or any psychotic disorder not otherwise specified * Current primary diagnosis of panic disorder, social phobia, generalized anxiety disorder, obsessive-compulsive disorder, or somatoform disorder Exclusion Criteria for Control Participants * Meets any of the overall exclusion criteria * Diagnosed with any medical or neurological illness * Diagnosed with any current or past psychiatric illness, as assessed by the SCID-I, including substance abuse or dependence (e.g., alcohol) * Has taken any medications that may have antidepressant properties (including some herbal supplements) within 2 weeks of study entry * Has taken any psychotropic medications within 2 weeks of study entry * Has taken any medications that may affect blood flow (including some blood pressure medications) within 2 weeks of study entry Exclusion Criteria for fMRI Studies: * Meets any of the overall exclusion criteria * Fails to meet safety standards for fMRI * Current back problems * Has strongly corrected vision, but does not wear contact lenses * Weighs more than 250 pounds or exceeds the limit of height-to-weight ratio for a comfortable fit in the scanner * Pregnant * Current alcohol or substance abuse * At risk for suicide or homicide