Comparison 2. Internet‐based cognitive and behavioural therapy (I‐C/BT) versus I‐non‐C/BT.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Severity of PTSD symptoms (post‐treatment)	2	82	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.08 [‐0.52, 0.35]
2.2 Severity of PTSD symptoms (follow‐up < 6 months)	2	65	Std. Mean Difference (IV, Fixed, 95% CI)	0.08 [‐0.41, 0.57]
2.3 Severity of PTSD symptoms (follow‐up 6–12 months)	1	18	Mean Difference (IV, Fixed, 95% CI)	‐8.83 [‐17.32, ‐0.34]
2.4 Dropouts	2	132	Risk Ratio (M‐H, Fixed, 95% CI)	2.14 [0.97, 4.73]
2.5 Severity of depressive symptoms (post‐treatment)	2	84	Std. Mean Difference (IV, Random, 95% CI)	‐0.12 [‐0.78, 0.54]
2.6 Severity of depressive symptoms (follow‐up < 6 months)	2	61	Std. Mean Difference (IV, Fixed, 95% CI)	0.20 [‐0.31, 0.71]
2.7 Severity of depressive symptoms (follow‐up 6–12 months)	1	18	Mean Difference (IV, Fixed, 95% CI)	‐8.34 [‐15.83, ‐0.85]
2.8 Severity of anxiety symptoms (post‐treatment)	2	74	Std. Mean Difference (IV, Random, 95% CI)	0.08 [‐0.78, 0.95]
2.9 Severity of anxiety symptoms (follow‐up < 6 months)	2	60	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.16 [‐0.67, 0.35]
2.10 Severity of anxiety symptoms (follow‐up 6–12 months)	1	18	Mean Difference (IV, Fixed, 95% CI)	‐8.05 [‐15.20, ‐0.90]