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.