Roles and effectiveness of lay community health workers in the prevention of mental, neurological and substance use disorders in low and middle income countries: a systematic review.

BACKGROUND: It has been suggested that lay community health workers (LHWs) could play a role in primary and secondary prevention of Mental, Neurological and Substance use (MNS) disorders in low resourced settings. We conducted a systematic review of the literature with the aim of assessing the existing evidence base for the roles and effectiveness of LHWs in primary and secondary prevention of MNS disorders in low and middle income countries (LMICs). METHODS: Internet searches of relevant electronic databases for articles published in English were done in August 2011 and repeated in June 2013. Abstracts and full text articles were screened according to predefined criteria. Authors were asked for additional information where necessary. RESULTS: A total of 15 studies, 11 of which were randomised, met our inclusion criteria. Studies were heterogeneous with respect to interventions, outcomes and LHWs' roles. Reduction in symptoms of depression and improved child mental development were the common outcomes assessed. Primary prevention and secondary prevention strategies were carried out in 11 studies and 4 studies respectively .There was evidence of effectiveness of interventions however, most studies (n = 13) involved small sample sizes and all were judged to have an unclear or high risk of bias. CONCLUSIONS: LHWs have the potential to provide psychosocial and psychological interventions as part of primary and secondary prevention of MNS disorders in LMICs, but there is currently insufficient robust evidence of effectiveness of LHW led preventive strategies in this setting. More studies need to be carried out in a wider range of settings in LMICs that control for risk of bias as far as possible, and that also collect indicators relating to the fidelity and cost of interventions.