Effectiveness of Acceptance and Commitment Therapy in treating depression and suicidal ideation in Veterans

This paper examines the effects of Acceptance and Commitment Therapy for depression (ACT-D), and the specific effects of experiential acceptance and mindfulness, in reducing suicidal ideation (SI) and depression among Veterans.

Patients included 981 Veterans, 76% male, mean age 50.5 years. Depression severity and SI were assessed using the BDI-II. Experiential acceptance and mindfulness were measured with the Acceptance and Action Questionnaire-II (AAQ-II) and the Five Facet Mindfulness Questionnaire, respectively.

Of the 981 patients, 647 (66.0%) completed 10 or more sessions or finished early due to symptom relief. For Veterans with SI at baseline, mean BDI-II score decreased from 33.5 to 22.9. For Veterans with no SI at baseline, mean BDI-II score decreased from 26.3 to 15.9. Mixed models with repeated measurement indicated a significant reduction in depression severity from baseline to final assessment (b = -10.52, p < .001). After adjusting for experiential acceptance and mindfulness, patients with SI at baseline demonstrated significantly greater improvement in depression severity during ACT-D treatment, relative to patients with no SI at baseline (b = -2.81, p = .001). Furthermore, increases in experiential acceptance and mindfulness scores across time were associated with a reduction in depression severity across time (b = -0.44, p < .001 and b = -0.09, p < .001, respectfully), and the attenuating effect of mindfulness on depression severity increased across time (b = -0.05, p = .042). Increases in experiential acceptance scores across time were associated with lower odds of SI across time (odds ratio = 0.97, 95% CI [0.95, 0.99], p = .016) and the attenuating effect of experiential acceptance on SI increased across time (odds ratio = 0.96, 95% CI [0.92, 0.99], p = .023). Overall the number of patients with no SI increased from 44.5% at baseline to 65% at follow-up.

Veterans receiving ACT-D demonstrated decreased depression severity and decreased odds of SI during treatment. Increases in experiential acceptance and mindfulness scores were associated with reduction in depression severity across time and increases in experiential acceptance scores were associated with reductions in SI across time.