Efficacy of Applied Relaxation as indicated preventive intervention in individuals at increased risk for mental...

The objective was to examine the efficacy of Applied Relaxation (AR) as indicated preventive intervention to reduce psychopathological symptoms and prevent incident mental disorders. In a parallel-group randomized controlled trial, N = 277 adults with elevated tension/distress, anxiety, or depressive symptomatology (Depression-Anxiety-Stress Scale, DASS-21) but no 12-month DSM-5 diagnosis of any mental disorder assessed via standardized interview (DIA-X-5) were randomized to an intervention group (IG; n = 139) receiving group-based AR training, or an assessment-only control group (CG, n = 138). Self-report questionnaires at baseline, post (immediately after the 10 week intervention or a similar time frame in CG) and 12-month follow-up included the DASS-21 as primary outcome measure of intervention efficacy. Incident subthreshold and threshold mental disorders were assessed via DIA-X-5 at 12-month follow-up as primary outcome of prevention efficacy. Intervention and prevention effects were examined on an intent-to-treat basis with missing data replaced using chained multiple imputation. Mixed-model analyses revealed accelerated symptom improvement in IG versus CG with a medium baseline-to-post between-group effect size (d = 0.59, 95%CI: 0.36-0.82). Logistic regression analysis revealed a significantly lower incidence rate for (sub-)threshold mental disorders until 12-month follow-up in IG (34.7%) versus CG (49.3%; Odds Ratio: 0.54, 95%CI: 0.31-0.92, Risk Ratio: 0.70, 95%CI: 0.51-0.96, Risk Difference = -0.15, 95%CI: -0.28 to -0.02). Group-based AR as a promising indicative preventive intervention should be tested in long-term studies and relative to a credible alternative intervention to assure that the intervention effects are not entirely due to demand characteristics, expectancies, or non-specific effects.