Sustained effectiveness and cost-effectiveness of the Healthy Activity Programme, a brief psychological treatment for depression delivered by lay counsellors in primary care: 12-month follow-up of a randomised controlled trial

Background: The Healthy Activity Programme (HAP), a brief behavioural intervention delivered by lay counsellors, enhanced remission over 3 months among primary care attendees with depression in peri-urban and rural settings in India. We evaluated the sustainability of the effects after treatment termination, the cost-effectiveness of HAP over 12 months, and the effects of the hypothesized mediator of activation on clinical outcomes. Methods and findings: Primary care attendees aged 18–65 years screened with moderately severe to severe depression on the Patient Health Questionnaire 9 (PHQ-9) were randomised to either HAP plus enhanced usual care (EUC) (n = 247) or EUC alone (n = 248), of whom 95% completed assessments at 3 months, and 91% at 12 months. Primary outcomes were severity on the Beck Depression Inventory–II (BDI-II) and remission on the PHQ-9. HAP participants maintained the gains they showed at the end of treatment through the 12-month follow-up (difference in mean BDI-II score between 3 and 12 months = −0.34; 95% CI −2.37, 1.69; p = 0.74), with lower symptom severity scores than participants who received EUC alone (adjusted mean difference in BDI-II score = −4.45; 95% CI −7.26, −1.63; p = 0.002) and higher rates of remission (adjusted prevalence ratio [aPR] = 1.36; 95% CI 1.15, 1.61; p