Sudden gains during cognitive-behavioral group therapy for anxiety disorders.

Sudden gains in psychotherapy are characterized by large and relatively stable decreases in psychiatric symptoms and have been associated with cognitive shifts in clients and shown to predict superior treatment outcomes in studies of depression and, to a lesser extent, anxiety disorders. The purpose of this study was to examine prevalence and impact of sudden gains during a transdiagnostic cognitive-behavioral group therapy (CBGT) for anxiety disorders, as well as the temporal relationship between sudden gains and cognitive changes. Data were used from two trials of transdiagnostic CBGT for anxiety disorders (n=130). Criteria for determining sudden gains in anxiety symptoms were based upon previous research on sudden gains from trials of cognitive-behavioral treatments for major depressive disorder. A total of 17 out of 98 (17.3%) clients experienced at least one sudden gain, with three clients showing two sudden gains during treatment. Three patients showing a sudden gain experienced a reversal of these gains, although one of these three had a subsequent second sudden gain. Clients experiencing sudden gains showed greater overall improvement following treatment than did clients who did not experience a sudden gain, with 65% of the sudden gainers' overall improvement accounted for by the sudden gain. Greater cognitive change in the pregain sessions was observed for clients with a sudden gain than those not showing a sudden gain. This finding lends support to the theory of cognitive mediation through CBGT in which substantial cognitive changes in pregain sessions lead to greater improvement overall.