Intervention to Prevent Major Depression in Primary Care: A Cluster Randomized Trial.

Background: Not enough is known about universal prevention of depression in adults. Objective: To evaluate the effectiveness of an intervention to prevent major depression. Design: Multicenter, cluster randomized trial with sites randomly assigned to usual care or an intervention. (ClinicalTrials.gov:NCT01151982) Setting: 10 primary care centers in each of 7 cities in Spain. Participants: Two primary care physicians (PCPs) and 5236 nondepressed adult patients were randomly sampled from each center; 3326 patients consented and were eligible to participate. Intervention: For each patient, PCPs communicated individual risk for depression and personal predictors of risk and developed a psychosocial program tailored to prevent depression. Measurements: New cases of major depression, assessed every 6 months for 18 months. Results: At 18 months, 7.39% of patients in the intervention group (95% CI, 5.85% to 8.95%) developed major depression compared with 9.40% in the control (usual care) group (CI, 7.89% to 10.92%) (absolute difference, -2.01 percentage points [CI, -4.18 to 0.16 percentage points]; P = 0.070). Depression incidence was lower in the intervention centers in 5 cities and similar between intervention and control centers in 2 cities. Limitation: Potential self-selection bias due to nonconsenting patients. Conclusion: Compared with usual care, an intervention based on personal predictors of risk for depression implemented by PCPs provided a modest but nonsignificant reduction in the incidence of major depression. Additional study of this approach may be warranted.