Early sudden gains in psychotherapy under routine clinic conditions: practice-based evidence.

Sudden gains--large, enduring reductions in symptom intensity from one session to the next--were identified by T. Z. Tang and R. J. DeRubeis (1999b) on the basis of data from 2 manualized clinical trials of cognitive therapy for depression. The authors found similar sudden gains among clients with a variety of disorders treated with a variety of approaches in routine clinic settings. Clients (N = 135 who met inclusion criteria) completed short forms of the Clinical Outcomes in Routine Evaluation (CORE-SF) preceding 7 to 74 individual sessions. Those who experienced sudden gains within their first 16 sessions (n = 23) had significantly lower CORE-SF scores in their final 3 sessions than did the other clients.