Table 2. Study characteristics, systematic review of mental health interventions by lay counsellors in low- and middle-income countries, 2000–2019.

Study	Study location	Study population	No. in intervention group	No. in control group	Primary intervention	No. of intervention sessions	Primary outcome measured	Effect size of intervention
								Hedges’ g	Categorya
Ali et al. (2003)47	Karachi, Pakistan (Qayoomabad community)	Adults aged 18–65 years	70	91	Cognitive behavioural therapy	8	Depression and anxiety (combined scores)	−0.608	Medium
Neuner et al. (2008)35	Nakivale refugee camp, Uganda	Rwandan and Somalian adults (average age: 35 years)	111	55	Narrative exposure therapy	6	PTSD	−0.549	Medium
Tol et al. (2008)40	Indonesia	Children (average age: 9 years)	182	211	Classroom-based cognitive behavioural therapy and creative play	15	PTSD	−0.675	Medium
Jordans et al. (2010)32	Nepal	Children aged 11–14 years	164	161	Classroom-based cognitive behavioural therapy and creative play	15	PTSD	−0.180	No effect
Patel et al. (2010)b43	Goa, India	Adults aged > 17 years	540	414	Interpersonal therapy	4–12	Depression	−0.327	Small
Patel et al. (2010)b,43	Goa, India	Adults aged > 17 years	387	414	Interpersonal therapy	4–12	Depression	0.160	No effect
Yeomans et al. (2010)41	Burundi	Adults (average age: 38.6 years)	37	38	Psychosocial education for PTSD	4	PTSD	−0.176	No effect
Connolly & Sakai (2011)30	Kigali, Rwanda	Adults aged > 18 years	71	74	Thought field therapy	1	PTSD	−0.781	Medium
Ertl et al. (2011)31	Uganda	War-exposed youth aged 12–25 years	28	28	Narrative exposure therapy	8	PTSD	−0.338	Small
Tol et al. (2012)39	Sri Lanka	Children in school grades 4–7 (aged 9–12 years)	199	200	Classroom-based cognitive behavioural therapy and creative play	15	PTSD	0.050	No effect
Connolly et al. (2013)29	Byumba, Rwanda	Adults aged > 18 years	85	79	Thought field therapy	1	PTSD	−1.351	Large
Meffert et al. (2014)33	Egypt	Sudanese adults in refugee camp aged 2–42 years	11	8	Interpersonal therapy	6	PTSD	−1.454	Large
O'Callaghan et al. (2014)36	Democratic Republic of the Congo	Children aged 7–18 years	79	80	Family-focused psychosocial support	8	PTSD	−0.405	Small
Tol et al. (2014)38	Burundi	Children aged 12–15 years	119	170	Classroom-based cognitive behavioural therapy and creative play	15	PTSD	0.020	No effect
Murray et al. (2015)34	Zambia	Children in refugee camp aged 5–18 years	131	126	Trauma-focused cognitive behavioural therapy	10–15	PTSD	−2.129	Large
Nadkarni et al. (2015)45	India	Male adults aged > 18 years	23	24	Counselling for alcohol problems	1–4	Alcohol use	−0.686	Medium
Robson et al. (2016)37	Uganda	Adults (average age: 46 years)	114	122	Thought field therapy	1	PTSD	−1.821	Large
Nadkarni et al. (2017)46	India	Adults aged 18–65 years	164	172	Counselling for alcohol problems	1–4	Alcohol use	−0.152	No effect
Patel et al. (2017)44	India	Adults aged 18–65 years	230	236	Healthy activity programme	6–8	Depression	−0.541	Medium
Dias et al. (2019)42	Goa, India	Adults aged > 60 years	80	84	Depression-in-later-life therapy	ND	Depression	−0.838	Large
Total	NA	NA	2825	2787	NA	NA	NA	NA	NA

NA: not applicable; ND: not determined; PTSD: post-traumatic stress disorder.

^a Effect sizes were categorized as: no effect (Hedges’ g: 0.0 to ±0.2); small effect (Hedges’ g: > ±0.2 to < ±0.5); medium effect (Hedges’ g: > ±0.5 to < ±0.8); and large effect (Hedges’ g: ≥ ±0.8).

^b The study by Patel et al. in 2010 reported on two trials.⁴³