Major depressive disorder (MDD) continues to have a profound impact on individuals, families, and the health care system. Despite marked success in treating active individual episodes of unipolar depression, our understanding of the neural and cognitive mechanisms involved in the return of symptoms remains extremely limited, and few interventions exist that specifically target factors involved in prophylaxis. The research being proposed is among the first that is designed to examine neurocognitive markers for depressive relapse vulnerability and link them directly to clinical prognosis.