This study will determine the effectiveness of continuation phase cognitive therapy versus antidepressant medication in preventing relapse of depression in people with recurrent depression.

Cognitive therapy (CT) is a short-term talking therapy that focuses on changing negative thinking patterns and helping patients develop coping skills to deal with their experiences. Evidence suggests that CT is effective in treating a number of psychiatric conditions, including anxiety and anger. This study will determine the effectiveness of cognitive therapy versus antidepressant medication or placebo in preventing relapse of depression in people with recurrent depression.

This study will last approximately 36 months and will comprise three phases. For the first 12 weeks, all participants will receive between 16 and 20 CT sessions. Participants will then be randomly assigned to receive additional CT sessions, antidepressants, or placebo for an additional 8 months. Upon completing treatment, participants will have follow-up study visits once every 4 months for the next 24 months. Clinician-rated scales and questionnaires will be used to assess depressive symptoms of participants at study start and at the end of each study phase.

Inclusion Criteria:

• Recurrent unipolar major depressive disorder
• Have experienced at least two episodes of major depression
• Have experienced at least one period of recovery during a depressive episode or have a history of dysthymia (a mood disorder characterized by depression) prior to the onset of current or past depressive episodes
• Willing and able to comply with all study requirements
• Able to speak and read English

Exclusion Criteria:

• Active alcohol or other substance dependence within 6 months prior to study entry
• Currently at risk for suicide
• Mood disorders due to a medical condition or substance abuse
• Bipolar, schizoaffective, obsessive compulsive, or eating disorders
• Schizophrenia
• Unable to stop mood-altering medications
• Current use of medication or diagnosis of a medical disorder that may cause depression (e.g., diabetes, head injury, stroke, cancer, multiple sclerosis)
• Previous failure to experience a reduction in depressive symptoms after 8 weeks of cognitive therapy with a certified therapist
• Previous failure to experience a reduction in depressive symptoms after 6 weeks of 40 mg of Prozac
• Pregnancy or plan to become pregnant in the next 11-12 months
• Unable to attend clinic twice weekly during business hours
• Unable to complete questionnaires