In this trial, fifty participants with current major depressive disorder who are not receiving an antidepressant medication and fifty healthy controls will complete questionnaires and computerized tasks to assess their decision-making styles. There will be three visits for depressed patients and two for healthy controls (the first and third visits). The first visit will involve interviews and questionnaires to assess the participant's level of depression, medical history and quality of life. Participants will then complete the decision-making tasks, and will earn between $5-40 based on their choices, in order to make the decisions on the computer tasks financially meaningful. At the completion of this visit, depressed patients will be prescribed an FDA-approved antidepressant, chosen in consultation with the treating psychiatrist. Patients will be responsible for paying for the prescription themselves. After two weeks on the medication, the patient will be seen for a follow-up visit to ensure tolerability of the medicine. After six weeks on the medicine, patients and healthy controls will return to repeat the questionnaires and the computer based decision-making tasks, and will again earn between $5-40 based on their performance.