Behavioral Experiments for Intolerance of Uncertainty: A Randomized Clinical Trial for Adults With Generalized Anxiety Disorder.

Sophisticated multicomponent treatments for adults with generalized anxiety disorder (GAD) have been developed over the past three decades. Although these comprehensive treatments have produced encouraging results, they appear to be less efficacious than treatments for other anxiety disorders. The goal of this randomized controlled trial is to test a newly developed, highly focused treatment for adults with GAD: Behavioral Experiments for Intolerance of Uncertainty. Sixty (60) participants (51 women, 9 men), with a mean age of 34.60 years (range: 19 to 67 years), were randomized to either treatment (n = 30) or wait-list control (n = 30). Treatment consisted of 12 weekly 1-hour sessions in which participants learned to use behavioral experiments to test their catastrophic beliefs about uncertainty. Assessments were conducted at pre-, mid- and postcondition, and at 6- and 12-month follow-up. The primary outcome was the severity of GAD, and secondary outcomes were worry, depression, somatic anxiety, and intolerance of uncertainty. Using growth curve modeling, we found that (1) the treatment group was superior to the wait-list group in terms of change from pre- to posttest on all outcomes; (2) the combined sample (once wait-listed participants received treatment) evidenced large and significant decreases on all outcomes; and (3) treatment gains were either maintained or increased over the 12-month follow-up period of the study. The new treatment is a promising treatment option for adults with GAD considering that it may be as efficacious as more comprehensive evidence-based psychological treatments for GAD.