Project 170589

Depression is a potentially lifelong illness with a high relapse risk. The proposed study extends our research program studying the role of cognitive reactivity as a risk factor for depressive relapse. Cognitive reactivity, the tendency of formerly depressed individuals to experience increased negative thinking when experiencing sad mood, is associated with an increased chance of experiencing a future depressive episode for these individuals. However, whether reducing cognitive reactivity leads to a reduced chance of experiencing a relapse of depression remains to be determined. Results from current and past research programs demonstrate that a psychological, relapse-prevention treatment, mindfulness-based cognitive therapy (MBCT) led to increased mindfulness and increased mindfulness was associated with reduced cognitive reactivity. This establishes that cognitive reactivity can be reduced by MBCT and that mindfulness may be a mechanism underlying reductions in cognitive reactivity. The proposed study will evaluate whether reductions in cognitive reactivity lead to reduced depressive relapse. In addition, it will evaluate whether MBCT, which teaches mindfulness and cognitive therapy (CT) skills, is necessary to reduce cognitive reactivity or whether CT is a sufficient treatment. In this study, formerly depressed individuals at high risk for depressive relapse will be randomly assigned to MBCT or CT or to a relaxation control group. These participants will be assessed as to their degree of cognitive reactivity both before and after the 8-week treatment period and then followed for an 18-month period to determine whether they experience a depressive relapse. This work has the potential to help all Canadians at risk for depressive relapse by leading to the development of more effective depression relapse prevention programs which could potentially lead to reduced rates of depressive relapse and a reduction in the overall prevalence of depression for Canadian

comparing MBCT vs CT vs relaxation control to evaluate cognitive reactivity as mechanism of depression relapse