Outcomes | Number of studies, number of participants (n) and a summary risk of bias | Findings and heterogeneity | Strength of evidence |

PTSD | 7 studies; n=650 Four low risks of bias studies | Pooled SMD=−0.96; 95% CI (−1.55 to −0.36); Q=40.6; df=7; p = 9.62E-7; I^{2}=82.8%; tau-squared=0.498 | Limited |

Depression | 4 studies; n=146 Three low risks of bias studies | Pooled SMD=−0.82; 95% CI (−1.69 to 0.05); Q=19.5046; df=4; p=0.0006; I^{2}=79.49%; tau-squared=0.7517 | Limited |

Anxiety | 3 studies; n=128 Three low risks of bias studies | Pooled SMD=−0.90; 95% CI (−1.87 to 0.07); Q=14.0716; df=3; p=0.0028; I^{2}=78.68%; tau-squared=0.7290 | Limited |

Common mental health symptoms | 4 studies; n=301 Three low risks of bias studies | Pooled SMD=−1.27; 95% CI (−2.31 to−0.23) Q=25.2; df=4; p=4.53E-5; I ^{2}=84.1%; tau-squared=1.12 | Limited |

Social support | 2 studies; n=52 Two low risks of bias studies | Pooled SMD=0.08; 95% CI (−0.49 to 0.64); Q=0.627; df=2; p=0.731; I^{2}=0%; tau-squared=0 | Moderate |

Coping | 1 studies; n=22 One low risk of bias study | Effect size=0.31; 95% CI (−0.53 to 1.16) | Limited |

Emotional problems (a comorbidity of mental health symptoms) | 1 study; n=43 One low risk of bias study | Effect size=0.48; 95% CI (−0.32 to 1.28) | Limited |

Negative sign of pooled SMD indicates a positive effect of mental health and psychosocial support (MHPSS), except for social support and coping.

n, number of participants; NET, narrative exposure therapy; PTSD, post-traumatic stress disorder; SMD, standardised mean difference.