. 2018 May 31;13(5):e0197102. doi: 10.1371/journal.pone.0197102

Table 2. Results of meta-analyses of effects of mental health first aid training on outcomes.

	N comparisons (k)	Cohen's d [95% CI]	p	I²% [95% CI]	Quality of the evidence (GRADE)
MHFA knowledge
Post	3	0.72 [0.59, 0.86]	<.001	0 [0, 90]	⊕⊕⊕⊕ High
< = 6-month follow-up	5	0.54 [0.43, 0.64]	<.001	0 [0, 79]	⊕⊕⊕⊕ High
>6-month follow-up	1	0.31 [0.09, 0.53]	.006		⊕⊕⊕⊝ Moderate^b
Recognition of mental health problem
Post	7	0.22 [-0.17, 0.61]	.276	40 [0, 75]	⊕⊕⊝⊝ Low^a^,^b
< = 6-month follow-up	11	0.52 [0.41, 0.64]	<.001	11 [0, 51]	⊕⊕⊕⊝ Moderate^a
>6-month follow-up	1	0.22 [-0.36, 0.80]	.450		⊕⊕⊝⊝ Low^a^,^b
Beliefs about effective treatments
Post	4	0.45 [0.11, 0.79]	.010	85 [63, 94]	⊕⊕⊕⊝ Moderate^a
< = 6-month follow-up	11	0.19 [0.07, 0.32]	.002	59 [20, 79]	⊕⊕⊕⊝ Moderate^a
Stigma
Post	8	0.14 [0.03, 0.25]	.010	0 [0, 68]	⊕⊕⊕⊝ Moderate^a
< = 6-month follow-up	14	0.14 [0.05, 0.23]	.003	48 [4, 72]	⊕⊕⊕⊝ Moderate^a
>6-month follow-up	1	0.08 [-0.14, 0.31]	.473		⊕⊕⊝⊝ Low^a^,^b
MHFA confidence
Post	7	0.58 [0.29, 0.87]	<.001	79 [57, 90]	⊕⊕⊕⊝ Moderate^a
< = 6-month follow-up	12	0.46 [0.31, 0.62]	<.001	77 [60, 87]	⊕⊕⊝⊝ Low^a^,^c
>6-month follow-up	2	0.21 [-0.09, 0.51]	.175	28^#	⊕⊕⊝⊝ Low^a^,^b
MHFA intentions
Post	4	0.75 [0.60, 0.91]	<.001	0 [0, 85]	⊕⊕⊕⊝ Moderate^a
< = 6-month follow-up	3	0.55 [-0.08, 1.18]	.085	91 [76, 96]	⊕⊕⊝⊝ Low^a^,^b
>6-month follow-up	2	0.26 [-0.12, 0.64]	.182	48^#	⊕⊕⊝⊝ Low^a^,^b
Amount of MHFA provided
Post	3	-0.06 [-0.32, 0.20]	.650	0 [0, 90]	⊕⊕⊝⊝ Low^a^,^b
< = 6-month follow-up	9	0.23 [0.08, 0.38]	.002	63 [23, 82]	⊕⊕⊕⊝ Moderate^a
>6-month follow-up	0
Quality of MHFA provided
Post	2	0.73 [-0.97, 2.43]	.399	94^#	⊕⊕⊝⊝ Low^a^,^b
< = 6-month follow-up	2	-0.01 [-0.22, 0.19]	.950	76^#	⊕⊕⊕⊝ Moderate^b
>6-month follow-up	1	0.25 [-0.17, 0.24]	.242		⊕⊕⊝⊝ Low^a^,^b
MHFA trainee mental health
Post	3	-0.04 [-0.39, 0.32]	.835	4 [0, 90]	⊕⊕⊝⊝ Low^a^,^b
< = 6-month follow-up	4	0.16 [-0.03, 0.35]	.093	0 [0, 85]	⊕⊕⊝⊝ Low^a^,^b
>6-month follow-up	1	0.02 [-0.20, 0.24]	.882		⊕⊕⊝⊝ Low^a^,^b
MHFA recipient mental health
Post	0
< = 6-month follow-up	2	0.14 [-0.05, 0.33]	.144	0^#	⊕⊕⊝⊝ Low^a^,^b
>6-month follow-up	1	-0.09 [-0.32, 0.14]	.458		⊕⊕⊕⊝ Moderate^b

# too few studies to calculate confidence interval.

GRADE Working Group grades of evidence:

High quality ⊕⊕⊕⊕: Further research is very unlikely to change our confidence in the estimate of effect.

Moderate quality ⊕⊕⊕⊝: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.

Low quality: ⊕⊕⊝⊝Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

Very low quality: ⊕⊝⊝⊝We are very uncertain about the estimate.

a Downgraded due to risk of bias.

b Downgraded due to imprecision.

c Downgraded due to publication bias.