A randomized controlled trial of guided internet-delivered cognitive behaviour therapy for older adults with generalized anxiety

•ICBT for older adults with generalized anxiety was compared to a waiting list condition.•ICBT participants improved more rapidly on measures of anxiety and depression.•Medium-to-large effect sizes were observed for ICBT participants on most measures.•Higher credibility of treatment ratings predicted faster improvement in anxiety.•Our study adds evidence to an emerging body of research on ICBT for older adults.

This study aimed to establish the efficacy of guided Internet-delivered cognitive-behaviour therapy (ICBT) for older adults with generalized anxiety disorder (GAD) or subclinical GAD. Participants were randomized to receive seven modules of ICBT (n = 24) or to a waiting list condition (WLC; n = 22). Faster improvements in symptoms of anxiety and depression were observed for participants in the ICBT condition relative to the WLC, with large between-group effect sizes on the Generalized anxiety disorder-7 (d = .85) and the Patient health questionnaire (d = 1.17) obtained at post-treatment. Further reduction in generalized anxiety symptoms was reported over the one-month follow-up. Treatment effects were replicated when control participants subsequently underwent treatment. Higher ratings of treatment credibility, but not expectancy, prior to ICBT predicted improvements over time. The results support the efficacy of ICBT as treatment for older adults with GAD.