Are psychological interventions for adult PTSD more efficacious and acceptable when treatment is delivered in higher frequency? A meta-analysis of randomized controlled trials

•160 RCTs demonstrate that psychological interventions can effectively reduce PTSD.•Efficacy of psychological interventions did not differ by session frequency.•Trauma-focused interventions were more tolerable when delivered more intensely.•The mechanisms behind this effect are unknown and systematic research is needed.•Tolerability of non-trauma-focused therapies did not differ by session frequency.