Abstract
We conducted a 26-month follow-up of a previously reported 12-month study that compared mindfulness-based cognitive therapy (MBCT) to a rigorous active control condition (ACC) for depressive relapse/recurrence prevention and improvements in depressive symptoms and life satisfaction. Participants in remission from major depression were randomized to an 8-week MBCT group (n = 46) or the ACC (n = 46). Outcomes were assessed at baseline; postintervention; and 6, 12, and 26 months. Intention-to-treat analyses indicated no differences between groups for any outcome over the 26-month follow-up. Time to relapse results (MBCT vs. ACC) indicated a hazard ratio = .82, 95% CI [.34, 1.99]. Relapse rates were 47.8% for MBCT and 50.0% for ACC. Piecewise analyses indicated that steeper declines in depressive symptoms in the MBCT vs. the ACC group from postintervention to 12 months were not maintained after 12 months. Both groups experienced a marginally significant rebound of depressive symptoms after 12 months but were still improved at 26 months compared to baseline (b = -4.12, p <= .008). Results for life satisfaction were similar. In sum, over a 26-month follow-up, MBCT was no more effective for preventing depression relapse/recurrence, reducing depressive symptoms, or improving life satisfaction than a rigorous ACC. Based on epidemiological data and evidence from prior depression prevention trials, we discuss the possibility that both MBCT and ACC confer equal therapeutic benefit. Future studies that include treatment as usual (TAU) control conditions are needed to confirm this possibility and to rule out the potential role of time-related effects. Overall findings underscore the importance of comparing MBCT to TAU as well as to ACCs.