Stage models for major depression: Cognitive behavior therapy, mechanistic treatment targets, and the prevention of stage transition.

Stage models encourage a longitudinal perspective on the care of those with major depression: supporting vigilance to the risk for stage progression and the selection of interventions to address that risk. A central goal for this article is to evaluate the role of cognitive-behavior therapy (CBT) in addressing stage progression in the treatment of major depression. We summarize the evidence supporting depression-focused CBT for: (1) preventing depression onset, (2) treating syndromal depression, (3) treating residual symptoms, (4) preventing relapse, and (5) addressing pharmacologic treatment resistance. In addition, consistent with the goal of aiding prevention and intervention development by refining mechanistic treatment targets, we evaluate the role of two specific risk-factors for stage progression: insomnia and rumination. These risk factors have a feed-forward relationship with stress, both being amplified by stress and amplifying the negative consequences of stress. Moreover, each of these risk factors predict depression stage transmissions across multiple stages, and both are modifiable with treatment. Accordingly, insomnia and rumination appear to serve as excellent mechanistic targets for the prevention of depression stage progression. These findings are discussed in relation to current limitations and future research directions for targeting these risk factors and furthering the effective treatment of depression.