Efficacy of interpersonal psychotherapy for post-traumatic stress disorder: A systematic review and meta-analysis

•Post-traumatic stress disorder is a condition that is associated with serious morbidity.•There is no clear consensus on the best first-line treatment for PTSD.•Interpersonal therapy (IPT) has been used successfully in the treatment of depressive disorders.•IPT's focus on interpersonal relationships is well-suited to the symptoms of PTSD.•There is currently no systematic summary of the efficacy of IPT in the treatment of PTSD symptoms.•IPT significantly reduced PTSD symptoms and was as effective as other active therapies such as medication and other psychotherapies.•This effect was particularly pronounced where 12 or more sessions were provided, in people who had a primary diagnosis of PTSD, and in people who had experienced natural disasters or mass violence.•Most studies modified the IPT protocol and did not comprehensively assess clinician fidelity to the protocol. The included studies generally had small sample sizes and were of limited quality. : Evidence for the efficacy of treatments for post-traumatic stress disorder (PTSD) is urgently required. This systematic review and meta-analysis examines the efficacy of interpersonal psychotherapy (IPT) in reducing the symptoms of PTSD. : Five databases were searched from inception until November 2018 to identify randomized controlled trials (RCTs) that assessed the efficacy of IPT in patients with PTSD symptoms. The reference lists of included studies were also hand searched. A random effects model was used to estimate changes in a clinician-administered PTSD scale, or self-reported symptoms. : Of 509 screened abstracts, ten clinical trials (11 study arms) involving 755 patients with PTSD symptoms were included. Nine studies (10 study arms) were included in the meta-analysis. The overall standardized mean difference was -0.44 (CI: -0.69, -0.19), p = 0.0005. This represents a change in the clinically administrated PTSD Scale (CAPS) of approximately 12 points. IPT was not superior to other active controls, such as medication and non-IPT psychotherapies, but was significantly superior to passive controls, such as waiting list and educational pamphlets. : Most studies modified the IPT protocol and did not comprehensively assess clinician fidelity to the protocol. The included studies generally had small sample sizes and were of limited quality. : IPT may be an effective treatment for PTSD, but clinical trials with larger sample sizes and improved methodology are required to confirm effects.