Background
There is a significant research gap in the field of universal, selective, and indicated prevention interventions for mental health promotion and the prevention of mental disorders. Barriers to closing the research gap include scarcity of skilled human resources, large inequities in resource distribution and utilization, and stigma.
Objectives
To assess the effectiveness of delivery by primary workers of interventions for the promotion of mental health and universal prevention, and for the selective and indicated prevention of mental disorders or symptoms of mental illness in lowâ and middleâincome countries (LMICs). To examine the impact of intervention delivery by primary workers on resource use and costs.
Search methods
We searched CENTRAL, MEDLINE, Embase, CINAHL, Global Index Medicus, PsycInfo, WHO ICTRP, and ClinicalTrials.gov from inception to 29 November 2021.
Selection criteria
Randomized controlled trials (RCTs) of primaryâlevel and/or community health worker interventions for promoting mental health and/or preventing mental disorders versus any control conditions in adults and children in LMICs.
Data collection and analysis
Standardized mean differences (SMD) or mean differences (MD) were used for continuous outcomes, and risk ratios (RR) for dichotomous data, using a randomâeffects model. We analyzed data at 0 to 1, 1 to 6, and 7 to 24 months postâintervention. For SMDs, 0.20 to 0.49 represented small, 0.50 to 0.79 moderate, and â„ 0.80 large clinical effects. We evaluated the risk of bias (RoB) using Cochrane RoB2.
Main results
Description of studies
We identified 113 studies with 32,992 participants (97 RCTs, 19,570 participants in metaâanalyses) for inclusion. Nineteen RCTs were conducted in lowâincome countries, 27 in lowâmiddleâincome countries, 2 in middleâincome countries, 58 in upperâmiddleâincome countries and 7 in mixed settings. Eightyâthree RCTs included adults and 30 RCTs included children. Cadres of primaryâlevel workers employed primary care health workers (38 studies), community workers (71 studies), both (2 studies), and not reported (2 studies). Interventions were universal prevention/promotion in 22 studies, selective in 36, and indicated prevention in 55 RCTs.
Risk of bias
The most common concerns over risk of bias were performance bias, attrition bias, and reporting bias.
Intervention effects
'Probably', 'may', or 'uncertain' indicates 'moderateâ', 'lowâ', or 'very lowâ'certainty evidence.
*Certainty of the evidence (using GRADE) was assessed at 0 to 1 month postâintervention as specified in the review protocol. In the abstract, we did not report results for outcomes for which evidence was missing or very uncertain.
Adults
Promotion/universal prevention, compared...