Critical review of outcome research on interpersonal psychotherapy for anxiety disorders

Background Interpersonal psychotherapy (IPT) has demonstrated efficacy in treating mood and eating disorders. This article critically reviews outcome research testing IPT for anxiety disorders, a diagnostic area where cognitive behavioral therapy (CBT) has dominated research and treatment. Methods A literature search identified six open and five controlled trials of IPT for social anxiety disorder (SAD), panic disorder, and posttraumatic stress disorder. Results Studies were generally small, underpowered, and sometimes methodologically compromised. Nonetheless, minimally adapted from its standard depression strategies, IPT for anxiety disorders yielded positive results in open trials for the three diagnoses. In controlled trials, IPT fared better than waiting list (N = 2), was equipotent to supportive psychodynamic psychotherapy (N = 1), but less efficacious than CBT for SAD (N = 1), and CBT for panic disorder (N = 1) in a methodologically complicated study. IPT equaled CBT in a group residential format (N = 1). Conclusions IPT shows some promise for anxiety disorders but has thus far shown no advantages in controlled trials relative to other therapies. Methodological and ecological issues have complicated testing of IPT for anxiety disorders, clouding some findings. The authors discuss difficulties of conducting non-CBT research in a CBT-dominated area, investigator bias, and the probable need to further modify IPT for anxiety disorders. Untested therapies deserve the fairest possible testing.