Another Interpersonal Psychotherapy Milestone

Interpersonal Psychotherapy (IPT) is turning 40. Klerman, Weissman and colleagues published the first IPT-outcome study for major depression in 1974, and their original IPT manual followed a decade later (Klerman et al., 1984). They conducted several IPT studies between those milestones, with a growing cadre of researchers contributing many more investigations. Now, interpersonal psychotherapy heads into early middle age with a steady, successful record of clinical research.

This issue of the American Journal of Psychotherapy, which is devoted to IPT, may stand both as a birthday celebration and a selective survey of interpersonal psychotherapy as it reaches maturity. Research has repeatedly demonstrated the efficacy of IPT for mood and eating disorders (Cuijpers et al., 2011; Barth et al., 2013; Kass et al., 2013) and shown preliminary benefit of IPT for some anxiety disorders (Markowitz et al., 2014). However, IPT has not shown efficacy in a trial for anorexia nervosa; it fared no better than supportive therapy, and its use was less well than sertraline for dysthymic patients, and it has shown no clear benefits in several studies in treating substance abuse (Weissman et al., 2007). Nonetheless, it was never intended as a universal treatment; outcome research has always determined the indications for IPT. Overall, the track record for IPT has been excellent, as is demonstrated by the therapy’s inclusion in numerous clinical treatment guidelines.

Relative to cognitive behavioral therapy, which spread widely almost from its inception, IPT was long a researcher’s, rather than a practitioner’s, treatment. Only in the past 10 to 15 years has it begun to spread more widely into clinical practice. The IPT manual has been updated (Weissman et al., 2000; 2007) and translated into many languages. Manuals of adaptations for specific treatment populations have been published (e.g., Frank, 2007; Markowitz, 1998; Mufson et al., 2011; Wilfley et al., 2000), and a recent casebook provides detailed clinical material to illustrate IPT techniques for clinicians (Markowitz & Weissman, 2012).

Several of the casebook authors, leading lights in IPT, are attending the birthday celebration by contributing to this issue of the American Journal of Psychotherapy. They address the world of IPT from varying perspectives. Myrna Weissman, Ph.D., who with the late Gerald L. Klerman, M.D., developed IPT, leads a review of the evolution of interpersonal counseling (IPC), a streamlined version of IPT intended for use by clinicians not trained in psychotherapy. Ellen Frank, Ph.D., who has conducted much innovative research in IPT, including major trials of maintenance IPT for recurrent major depression and of interpersonal social rhythms therapy (IPSRT) for bipolar disorder, with her colleagues, describes innovative developments in the world of IPT research. Laura Mufson, Ph.D., who adapted IPT for depressed adolescents (IPT-A), explores with her colleagues cultural facets of its use. Holly Swartz, M.D. and coauthors provide a helpful review of the literature on eight-session IPT (IPT-B), her briefer version of an already short-term, time-limited treatment. Paula Ravitz, M.D., the IPT expert who has most devoted herself to studying IPT training from an educational perspective, and her coauthors use IPT dissemination as an example of more general research in psychotherapy training and dissemination. Carlos Blanco, M.D., Ph.D. and colleagues describe the application of IPT to depressed women patients struggling with the role transition of breast cancer, a pilot study whose encouraging findings have led to an ongoing, federally funded randomized controlled efficacy trial.

Both like and unlike other psychotherapies, IPT faces an uncertain future. Interpersonal psychotherapy is spreading: more clinicians are learning IPT. Much more dissemination could occur, The International Society for Interpersonal Psychotherapy holds biennial meetings. And based on the empirical research track record, IPT should be required training in psychiatric residency and graduate mental health programs. Yet with dissemination comes the risk of dilution and fragmentation: though it was carefully controlled in research protocols, as IPT spreads in clinical practice it may diversify—and possibly digress from its empirically based roots.

The clinical indications for and the technical evolution of IPT were always derived from its clinical research results. Pilot studies (many described by Frank et al. in this issue, and one illustrated by Blanco et al.) lead to comparative efficacy trials, and thence to effectiveness studies (like those several of this issue’s papers report). We know that IPT works for many patient populations, but we need to know much more about its mechanism(s). Why does it work (Lipsitz and Markowitz, 2013)? Psychotherapy research currently faces a difficult funding environment (at least in the United States) that may make it much harder to obtain crucial answers to this question. The reader may wish to keep these issues in mind while reading the excellent articles that follow.