Thirteen studies (793 participants) were included in the review. Nine studies were randomised controlled trials, two studies were pre-post treatment designs and two studies did not report design. Drop-outs ranged from 8% to 47% for treatment groups and 2% to 48% for comparison groups.
Post-traumatic stress disorder symptom outcomes: Overall there were small but significant improvements in post-traumatic stress disorder symptoms for telehealth interventions compared with comparison conditions (d=0.27, 95% CI 0.10 to 0.45; 11 studies). There were also improvements in treatment effects for telehealth treatment compared with a waiting list comparison group (d=1.01, 95% CI 0.76 to 1.26; five studies). There were no significant differences between telehealth treatment and a supportive counselling telehealth comparison group (two studies). A telehealth intervention was less effective than a face-to-face intervention (d=-0.68, 95% CI -0.39 to -0.98; four studies). Telehealth treatments were associated with significant pre to post reduction for post-traumatic stress disorder symptoms (ESsg 0.99, 95% CI 0.87 to 1.11; 12 studies). There was evidence of statistical heterogeneity for the comparison of telehealth treatment with face-to-face treatment (Q=3.07) and the pre-post treatment analysis.
Depression symptom outcomes: Telehealth interventions were more effective than wait-list control groups (d=0.80, 95% CI 0.56 to 1.05; five studies). There were no significant differences between telehealth treatment and face-to-face interventions (three studies). There was no significant statistical heterogeneity for either of these analyses. Telehealth treatments were associated with a significant within-group improvement for depression symptoms (ESsg 0.98, 95% 0.86 to 1.10; 11 studies). There was significant statistical heterogeneity for this analysis (Q=66.47).
There was no evidence of significant publication bias.