What is the main aim of this review?
The aim of this Cochrane Review was to assess the effects of involving people in primary services and the community, such as nurses, midwives, teachers or caregivers, to promote mental health. The review focused on children and adults living in low- and middle-income countries.
Key messages
The employment use of primary-level and community workers may improve the mental health of adults and children living in low- and middle-income countries. However, more evidence is needed.
What was studied in this review?
Many people who would benefit from mental health support cannot access these services. One reason for this is a lack of specialized mental healthcare staff. This is especially true in low- and middle-income countries. To overcome this barrier, people without a professional background in mental health, such as nurses or teachers, can be trained to deliver some mental health services. In our review, we investigated whether this strategy helps to promote mental health and prevent mental disorders amongst adults and children. We also assessed its costs.
What are the main results of this review?
We included 113 studies from a range of low- and middle-income countries.
The studies assessed the effects of services carried out by primary-level and community workers on people's mental health, quality of life, and social outcomes.
We grouped interventions depending on their overall objectives. Specifically, we refer to those targeting the whole population as 'promotion/universal prevention', those targeting people at risk for developing a mental disorder as 'selective prevention', and those designed for already presenting some sign of mental disorders as 'indicated prevention'. Below we report evidence of the results of low to moderate-certainty, directly after the intervention. We did not present results for outcomes for which there was no or very uncertain evidence.
Promotion/universal prevention interventions, compared to usual care:
- probably slightly reduced anxiety symptoms in adults
- may slightly reduce distress/PTSD symptoms in adults
- may improve the quality of life of children
- may reduce adverse events in children
- may slightly reduce depression symptoms in children
- may slightly reduce anxiety symptoms in children
Selective prevention interventions, compared to usual care:
- probably slightly reduced depressive symptoms in adults
- may slightly reduce functional impairment in children
- probably slightly reduced depressive symptoms in children
- may slightly reduce anxiety symptoms in children
- probably slightly reduced distress/PTSD symptoms in children
Indicated prevention interventions, compared to usual care:
- may reduce adverse events in adults
- probably slightly reduced functional impairment in adults
- decreased slightly functional impairment in children
- decreased slightly depressive symptoms in children
- may slightly reduce distress/PTSD symptoms in children
Indicated prevention interventions delivered through task-shifting may improve mental health outcomes.
What are the limitations of the evidence?
The limitations of the evidence in this review stem from the absence of assessments related to the reduction in the incidence of mental disorders in the prevention studies, and the lack of discernible differences in acceptability. Furthermore, the limited number of randomized controlled trials reporting our secondary outcomes, and their low quality, failed to demonstrate clinically significant advantageous effects of the studied prevention interventions for some outcomes in both child and adult populations.
How up-to-date is the review?
Review authors searched databases up to November 2021 to find and include all relevant published and unpublished trials.
The evidence indicated that prevention interventions delivered through primary workers - a form of task-shifting - may improve mental health outcomes. Certainty in the evidence was influenced by the risk of bias and by substantial levels of heterogeneity. A supportive network of infrastructure and research would enhance and reinforce this delivery modality across LMICs.
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.
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 low- and middle-income countries (LMICs). To examine the impact of intervention delivery by primary workers on resource use and costs.
We searched CENTRAL, MEDLINE, Embase, CINAHL, Global Index Medicus, PsycInfo, WHO ICTRP, and ClinicalTrials.gov from inception to 29 November 2021.
Randomized controlled trials (RCTs) of primary-level 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.
Standardized mean differences (SMD) or mean differences (MD) were used for continuous outcomes, and risk ratios (RR) for dichotomous data, using a random-effects model. We analyzed data at 0 to 1, 1 to 6, and 7 to 24 months post-intervention. For SMDs, 0.20 to 0.49 represented small, 0.50 to 0.79 moderate, and ≥ 0.80 large clinical effects. We evaluated the risk of bias (RoB) using Cochrane RoB2.
Description of studies
We identified 113 studies with 32,992 participants (97 RCTs, 19,570 participants in meta-analyses) for inclusion. Nineteen RCTs were conducted in low-income countries, 27 in low-middle-income countries, 2 in middle-income countries, 58 in upper-middle-income countries and 7 in mixed settings. Eighty-three RCTs included adults and 30 RCTs included children. Cadres of primary-level 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 'moderate-', 'low-', or 'very low-'certainty evidence.
*Certainty of the evidence (using GRADE) was assessed at 0 to 1 month post-intervention 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 to usual care:
- probably slightly reduced anxiety symptoms (MD -0.14, 95% confidence interval (CI) -0.27 to -0.01; 1 trial, 158 participants)
- may slightly reduce distress/PTSD symptoms (SMD -0.24, 95% CI -0.41 to -0.08; 4 trials, 722 participants)
Selective prevention, compared to usual care:
- probably slightly reduced depressive symptoms (SMD -0.69, 95% CI -1.08 to -0.30; 4 trials, 223 participants)
Indicated prevention, compared to usual care:
- may reduce adverse events (1 trial, 547 participants)
- probably slightly reduced functional impairment (SMD -0.12, 95% CI -0.39 to -0.15; 4 trials, 663 participants)
Children
Promotion/universal prevention, compared to usual care:
- may improve the quality of life (SMD -0.25, 95% CI -0.39 to -0.11; 2 trials, 803 participants)
- may reduce adverse events (1 trial, 694 participants)
- may slightly reduce depressive symptoms (MD -3.04, 95% CI -6 to -0.08; 1 trial, 160 participants)
- may slightly reduce anxiety symptoms (MD -2.27, 95% CI -3.13 to -1.41; 1 trial, 183 participants)
Selective prevention, compared to usual care:
- probably slightly reduced depressive symptoms (SMD 0, 95% CI -0.16 to -0.15; 2 trials, 638 participants)
- may slightly reduce anxiety symptoms (MD 4.50, 95% CI -12.05 to 21.05; 1 trial, 28 participants)
- probably slightly reduced distress/PTSD symptoms (MD -2.14, 95% CI -3.77 to -0.51; 1 trial, 159 participants)
Indicated prevention, compared to usual care:
- decreased slightly functional impairment (SMD -0.29, 95% CI -0.47 to -0.10; 2 trials, 448 participants)
- decreased slightly depressive symptoms (SMD -0.18, 95% CI -0.32 to -0.04; 4 trials, 771 participants)
- may slightly reduce distress/PTSD symptoms (SMD 0.24, 95% CI -1.28 to 1.76; 2 trials, 448 participants).