This study will determine the effectiveness of mindfulness-based cognitive therapy (MBCT) in preventing depression relapse.

Depression is a serious condition that can cause significant social and emotional problems and reduce the overall quality of life. Relapses in depressive episodes are common and may result in a patient's reluctance to follow a treatment regimen, thus making the episode more severe. Safe and effective therapies to prevent depression relapse are needed. This study will compare three different approaches to determine which is most effective in preventing relapses in depressive episodes.

This study will comprise 2 parts. In Part 1, all participants will receive antidepressant medication for 6 months. Participants whose depression symptoms do not improve will complete their study participation at the end of Part 1. Participants who respond to their regimen will be enrolled in Part 2. This part will last 18 months. During Part 2, participants will be randomly assigned to one of three groups. Participants in Group 1 will continue the drug regimen they began in Part 1. Participants in Group 2 will discontinue their antidepressants and attend an 8-week relapse prevention program. This MBCT program is designed to help participants learn skills that can increase their awareness and change their reaction to stressful events. Participants in Group 3 will have their antidepressant medication from Phase 1 switched to a placebo without their knowledge. Self-report scales will be used to assess the depressive symptoms of participants at the beginning of the study, at the end of Phase 1, and at the end of the study, after Phase 2.

Inclusion Criteria:

• Meet DSM criteria for recurrent major depressive disorder, defined as at least one major depressive episode within 3 years prior to study entry AND at least 2 months of normal functioning following the episode

Exclusion Criteria:

• Depression secondary to a concurrent medical disorder
• Current use of medication that could cause depressive symptoms
• A rating of level 2 or higher on the Index of Treatment Refractory Depression
• Current diagnosis of any of the following psychiatric disorders: psychotic or organic mental, bipolar, primary obsessive compulsive, borderline personality, antisocial personality, or eating
• Current diagnosis of comorbid chronic depression that is disabling
• Current substance abuse
• Score less than 14 on the Hamilton Rating Scale for Depression-17 (HRSD-17)
• At risk for suicide
• Pregnancy or plan to become pregnant during the study
• Practice meditation more than once a week or yoga more than twice a week at study entry