Behavioral Activation for Depression and Habitual Rumination

Symptom severity measured by the BDI-2,Disorder severity assessed with the DIAMOND diagnostic interview - Major Depressive Disorder,Diagnostic status assessed with the DIAMOND diagnostic interview - Major Depressive Episode

Depressive rumination, a negative thinking style characterized by repetitive and passive
 thoughts about the causes, meanings, and consequences of one's feelings and distress, is
 often described as being a habitual response tendency that forms a vulnerability to
 depression. Behavioural Activation (BA) is an effective treatment for depression but little
 is known of mechanisms of changes during a successful treatment completion and for whom the
 treatment benefits the most. The main purpose of the study is to investigate whether
 habit-like mood-reactive rumination will change during Behavioral Activation treatment for
 current depression and mediates symptom changes in the treatment. Important moderators of
 change will also be investigated (i.e. history of early life stress and cognitive
 flexibility). We aim to provide individual BA treatment for up to 130 currently depressed
 participants in 12 treatment sessions over 11 weeks. Measures are obtained at pre-treatment,
 during treatment, at post-treatment and at 6 month follow up.