Primary Prevention of Major Depression Based on the Level and Profile of Risk of Primary Care Attenders: Cluster, Controlled, Randomised Trial

The main objective is to measure the effectiveness of a new intervention for primary prevention of major depression based on the level and profile of risk of primary care attendees. Among the secondary objectives is to evaluate the cost-effectiveness and cost-utility of the intervention versus usual care. METHODS: This is a cluster, randomised controlled trial of a community intervention with cluster at the level of practice. It will be undertaken in primary medical care in 7 Spanish cities and 5 autonomous communities.The aim is to evaluate a new intervention for primary prevention of major depression based on patients' level and profile of risk. Family doctors in the intervention practices will provide the intervention for patients at risk. Patients at risk who are recruited in control practices will receive usual primary care. The main outcome is the accumulated incidence of major depression (measured by CIDI) during the follow-up. The investigators will assess main outcomes and other covariables at baseline, 6, 12, and 18 months. A random sample of 3,381 primary care attendees (1,690 for each arm), aged 18-75 and without major depression will be recruited in 70 health centres (140 family doctors) in 7 cities. The investigators shall undertake a logistic regression multilevel model with 4 levels (time, patient, doctor and health centre). The investigators shall also undertake multivariate gamma and quantile regression to assess respectively the cost-effectiveness and cost-utility of the new intervention versus usual care, estimating their standard errors by bootstrap.