Predictors of Outcome of Acceptance and Commitment Therapy and Cognitive Behavioral Therapy in Older Adults With Anxiety Symptoms.

A recent trial in older adults with anxiety symptoms in primary care found no differences in outcome between an ACT and CBT intervention. The current study aimed to identify moderators and non-specific predictors of treatment response to these two interventions. The sample consisted of 314 older adults who were randomized to either ACT or CBT. Anxiety symptom severity (measured with the GAD-7) was the main outcome variable. Demographics, (psycho)pathology, social support, and psychological processes were examined as predictors. No moderator variables were identified. More severe anxiety and depression symptoms at baseline predicted a worse short- and long-term response to ACT and CBT, while higher levels of mastery predicted a better short-term treatment response in both conditions. When interpreting these results, the lack of sufficient statistical power to detect multiple modest interaction effects should be taken into account. Based on the results of the present study, it is not possible to allocate patients to the intervention that is likely to be most effective for them. The prognostic effects of anxiety and depression symptom severity and mastery may hold implications regarding treatment enhancement strategies in general. The study was registered in the Netherlands Trial Register (NL6131; NTR6270).