Sudden gains and outcome: a broader temporal analysis of cognitive therapy for depression.

Individual Beck Depression Inventory (BDI) time courses of 38 clients receiving cognitive therapy (CT) and a modified form of CT were studied in order to investigate temporal changes during CT for depression. The primary aim was to determine if alternative methods of defining and computing gains occurring early in CT would alter the conclusions drawn in the current literature. Three types of gains were studied: sudden gains (previously studied sudden, substantial, and stable improvements in depression during 1 between-session interval after Session 2), first-session gains (occurring after first sessions), and pretreatment gains (occurring after pretreatment assessments). Positive outcomes were predicted by first-session gains and by sudden gains occurring in the first half of treatment, highlighting the importance of early change in CT for depression.