Table 4

Outcomes and key findings of the studies included in the systematic review

No	Author (year)	Location	Economic status	Outcome measure	Outcome type	Outcome method	Significance	Key findings
1	Abas et al (2016)	Zimbabwe	Low income	Satisfaction, attitude, clinical outcome	Mixed	Interview/focus group		Training was positively received by patients, and was found rewarding for lay health workers to deliver.
2	Abayomi et al (2012)	Nigeria	Lower middle income	Attitude	Quantitative	Questionnaire	Significant improvement	Training reduced perceived dangerousness and improved attitude towards persons with mental health problems.
3	Adebowale et al (2015)	Nigeria	Lower middle income	Clinical skills	Quantitative	Vignette	Significant improvement	Training improved knowledge and expected mental health practice with greater effect on case management than case recognition.
4	Alonso et al (2014)	Sierra Leone	Low income	Clinical outcome, clinical practice	Quantitative	Questionnaires, case record examination		Trained primary health workers could deliver safe and effective treatment for mental health disorders.
5	Armstrong et al (2010)	Australia	High income	Confidence, clinical skills	Quantitative	Questionnaire, interview	Significant improvement	Training improved objective competence and subjective confidence in delivering cognitive behavioural therapy.
6	Armstrong et al (2011)	India	Lower middle income	Attitude, clinical skills	Quantitative	Vignette	Significant improvement	Training improved ability to recognise mental disorders, reduced faith in unhelpful interventions and reduced stigmatising attitudes.
7	Bowers and Burnett (2009)	UK	High income	Confidence and knowledge	Quantitative	Questionnaire		Training increased confidence regarding mental health disorder assessments and in making clinical diagnoses.
8	Chew-Graham et al (2014)	UK	High income	Clinical practice, satisfaction	Qualitative	Interview/focus group		Training increased awareness, recognition and respect for the needs of patients from under-served communities.
9	Chibanda et al (2016)	Zimbabwe	Low income	Clinical outcome	Quantitative	Questionnaire	Significant improvement	Lay health worker-administered, primary care-based problem-solving therapy with education and support improved patient symptoms.
10	Church et al (2010)	Canada	High income	Attitude, clinical practice, confidence, satisfaction	Mixed	Questionnaire, written feedback, interview/focus group, facilitator’s notes	Significant improvement	Training heightened awareness of and improved confidence in mental health issues and interventions, while increasing interprofessional collaborations.
11	Cook et al (2017)	USA	High income	Attitude, clinical practice, knowledge	Mixed	Questionnaire		Trainees’ professional diversity increased over time. Health professionals had higher scores on some outcome variables than non-health professionals.
12	Ekers et al (2013)	UK	High income	Clinical outcome and satisfaction	Mixed	Questionnaire		Trainees found the training acceptable and useful.
13	Ferraz and Wellman (2009)	UK	High income	Clinical practice, knowledge	Quantitative	Questionnaire	Significant improvement	Training increased participants’ knowledge and understanding of solution-focused brief therapy and their use of the techniques in routine clinical practice.
14	Hofmann-Braussard et al (2017)	India	Lower middle income	Attitude, confidence, knowledge	Mixed	Questionnaire, vignette	Significant improvement	Training increased ability to recognise mental health disorders, decreased stigma and increased competence in working with people who have poor mental health.
15	Hossain et al (2010)	Australia	High income	Confidence, knowledge, satisfaction	Mixed	Interview/focus group		Training improved participants’ confidence in and knowledge of mental health issues and increased their empathy toward persons with mental health problems.
16	Jenkins et al (2013)	Kenya	Lower middle income	Clinical outcome, clinical skills	Quantitative	Questionnaire, clinical notes	Significant improvement	Training showed no effect on recorded diagnostic rates of mental health disorders, but improved patient outcomes.
17	Jordans et al (2012)	Nepal	Low income	Knowledge	Quantitative	Questionnaire, vignette	Significant improvement	Training improved mental health literacy for complex emergencies.
18	Kauye et al (2014)	Malawi	Low income	Clinical skills	Quantitative	Questionnaire, clinical notes	Significant improvement	Training improved quality of detection and management of patients with mental health disorders.
19	Lam et al (2016)	Hong Kong (China)	High income	Attitude, confidence, clinical practice	Mixed	Questionnaire	Significant improvement	Training improved confidence in the recognition, diagnosis and management of mental health issues.
20	Li et al (2014)	China	Upper middle income	Attitude and knowledge	Quantitative	Questionnaire, vignette	Significant improvement	Training did not have an effect on knowledge, but improved attitude towards people with mental health problems.
21	MacCarthy et al (2013)	Canada	High income	Attitude, confidence, clinical outcome, clinical practice, satisfaction	Quantitative	Questionnaire	Significant improvement	Training had a positive impact on patient outcomes and decreased stigmatising attitudes.
22	Morawska et al (2013)	Australia	High income	Attitude, clinical skills	Mixed	Questionnaire, vignette, interview/focus group	Significant improvement	Training increased recognition of mental illnesses, confidence in providing help and treatment and reduced stigmatising attitudes with positive long-term effects.
23	Paudel et al (2014)	India	Lower middle income	Attitude, knowledge, practice	Qualitative	Focus group		Training improved the identification of symptoms and ability to suggest management options and increased empathetic attitudes towards patients.
24	Ravitz et al (2013)	Canada	High income	Attitude, clinical skills, confidence, knowledge	Mixed	Questionnaire, focus group	Significant improvement	Training heightened knowledge in mental health issues, improved confidence, morale, practice behaviour changes.
25	Ruud et al (2016)	Norway	High income	Attitude, clinical skills, practice, satisfaction	Qualitative	Questionnaire, interview		Training improved recruitment, satisfaction among participants and service managers, strengthened clinical competence, increased understanding and mutual respect between professional groups and service levels, and increased focus on user involvement and influence.
26	Sadik et al (2011)	Iraq	Upper middle income	Attitude, clinical skills, clinical practice, knowledge, satisfaction	Quantitative	Questionnaire, clinical notes, interview	Significant improvement	Training improved knowledge in mental health issues, and demonstration of practical skills in the workplace.
27	Siriwardhana et al (2016)	Sri Lanka	Lower middle income	Knowledge, satisfaction	Mixed	Questionnaire, interview		Training improved overall knowledge in mental illnesses and mental healthcare.
28	Usher et al (2014)	Pacific Island Small States	Aggregates	Attitude, clinical skills, knowledge	Quantitative	Questionnaire	Significant improvement	Training improved the knowledge, skills and attitudes of people who care for persons experiencing mental health problems.
29	Wright et al (2014)	Malawi	Low income	Confidence, clinical practice, clinical skills, knowledge	Mixed	Questionnaire, clinical notes	Significant improvement	Training had positive effect on knowledge and confidence in providing care, and increased mental health promotion activity.