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Markowitz, J.C., Petkova, E., Neria, Y., Van Meter, P.E., Zhao, Y., … Marshall, R.D. (2015). Is exposure necessary? A randomized controlled trial of Interpersonal Psychotherapy for PTSD. American Journal of Psychiatry, 172, 1-11.

Post-traumatic stress disorder (PTSD) is a condition caused by experiencing or witnessing a terrifying event. Symptoms may include flashbacks, nightmares and severe anxiety, as well as uncontrollable thoughts about the event. PTSD has a lifetime prevalence of 6.8%, which makes it a highly prevalent disorder. The main technique of empirically validated psychological treatments for PTSD involve exposing patients to safe reminders of the trauma including memories, with the intent of extinguishing the fear responses. This is the basis of cognitive behavioural therapy (CBT) with prolonged exposure, which is a consensus treatment for PTSD. However, not all patients benefit from CBT with prolonged exposure, and such treatment may be too difficult for some patients and therapists to tolerate. Markowitz and colleagues argued that PTSD symptoms reflect interpersonal issues including interpersonal withdrawal, mistrust, and hypervigilence. Interpersonal psychotherapy (IPT) is a time-limited efficacious treatment for depression that was adapted for this study for non-exposure based non-CBT treatment of PTSD. IPT was modified so that the first half of treatment focused on recognizing, naming, and expressing feelings in non-trauma related interpersonal situations. The second half of treatment focused on common IPT themes such as role disputes and role transitions. The authors argued that IPT helps individuals with PTSD gain mastery over social interactions and mobilize social supports. The authors conducted a randomized controlled trial that had a sufficient sample size to test a hypothesis of “non-inferiority”, that is to adequately test if PTSD and exposure based CBT were equally effective. Both treatments were compared to a progressive muscle relaxation (PMR) control condition. In all, 110 participants with chronic PTSD were recruited and randomized to IPT, CBT, or PMR. Most patients reported trauma of 14 years duration from either sexual or physical abuse, and half had a current comorbid depression. All three interventions resulted in large significant reductions in PTSD symptoms. IPT (63%) and CBT (47%) were not significantly different in rates of response (i.e., in which response was defined as 30% improvement in a clinician administered PTSD scale), but IPT had a significantly higher response rate than PMR (38%). Patients with comorbid depression were more likely to drop out of CBT with prolonged exposure than IPT.

Practice Implications

The results of the study suggest that IPT and CBT with exposure were equally effective in reducing symptoms of PTSD. It is important to keep in mind that this is one well-conducted trial that needs to be replicated by independent researchers in order to establish if the findings are truly reliable. Nevertheless, the findings contradict the widespread belief that patients with PTSD require exposure-based treatment in order to improve. IPT may be another option for the treatment of PTSD, especially for patients who cannot tolerate the prolonged exposure. Patients with comorbid depression may have the most difficulty tolerating prolonged exposure therapy, and so they may benefit from IPT as an alternative. IPT may help patients gain abilities in social interactions and social support, which may make it easier for them to spontaneously expose themselves to recollections of trauma.

Lemmens, L.H.J.M., Arntz, A., Peeters, F., Hollon, S.D., Roefs, A., & Huibers, M.J.H. (2015). Clinical effectiveness of cognitive therapy v. interpersonal psychotherapy for depression: Results of a randomized controlled trial. Psychological Medicine, doi:10.1017/S0033291715000033

Generally, I prefer to report on meta analyses rather than individual studies mainly because findings from meta analyses are based on a larger number of studies and so are more reliable (see my November, 2013 blog). However, this study by Lemmens and colleagues represents a large clinical trial of 182 depressed patients who were randomized to cognitive therapy (CT), interpersonal psychotherapy (IPT), or a no-treatment control condition. The size of the trial provided the study with enough statistical power to test a hypothesis of non-inferiority of treatments. (A statistical note: A study finding of “non-inferiority” between treatments is sometimes unreliable because it is easier to detect such a finding with a small or poorly designed study. Studies with larger sample sizes provide greater statistical power, which in part makes a non-inferiority finding more reliable). A previous meta analysis showed both CT and IPT to be equally effective interventions for major depression. However, none of the studies in that meta analysis had sufficiently large sample sizes to reliably detect non-inferiority of interventions, none reported outcomes after post-treatment, and none of the studies used a no-treatment comparison condition. In their study, Lemmens and colleagues provided 16 to 20 sessions of individual therapy (45 minutes in length) to participants who met criteria for major depressive disorder. CT was based on Beck’s model and focused on identifying and altering cognitions, schemas, and attitudes associated with negative affect. IPT seeks to understand the social and interpersonal context of a patient’s depressive symptoms, and helps the patient to solve the interpersonal problem or change their relation to the problem, which may result in a resolution of the depressive symptoms. The study by Lemmens and colleagues was well designed in which: patients were randomized to conditions (CT, IPT, wait-list), 10 licensed therapists were expertly trained (5 CT therapists, 5 IPT therapists), and the therapies were competently delivered. Depressive symptoms significantly decreased for patients in both CT and IPT conditions with large effects, and these findings remained stable to 5 months post treatment. There were no differences between CT and IPT at post treatments and follow up, and both treatments were more effective than the waitlist control condition. Half of the sample had clinical improvements in symptoms, and 37% of patients were without depressive symptoms at 1 year follow up.

Practice Implications

CT and IPT did not differ in the treatment of depression in the short (post-treatment) and long term (follow up). The study does not address why two very different treatments led to similar positive outcomes. The authors suggest two possible reasons: (1) different specific treatment pathways led to similar results, or (2) change was driven by factors common to both treatments like motivation and therapeutic alliance.

Driessen, E., Van, H.L., Don, F.J., Peen, J., Kool, S. ....Dekker, J.J. (2013). The efficacy of cognitive-behavioral therapy and psychodynamic therapy in the outpatient treatment of major depression: A randomized clinical trial. American Journal of Psychiatry, 170, 1041-1050.

Psychotherapy is one of the most widely used treatments for major depression. Unfortunately there is no commercial entity like the pharmaceutical industry to support research and development of psychotherapy. As a result, researchers have limited ability to conduct larger-scale studies of comparative treatment effectiveness, of which there are only a handful. Although psychodynamic therapy (PDT) has been used to treat depressed patients for decades, randomized controlled trials of its efficacy are relatively infrequent. A concurrent problem with outcome research in psychotherapy is that sample sizes tend to be too small to actually test if two treatments are equivalent in what is called an “equivalency trial”. Without large samples, all one can conclude is that two treatments are “not significantly different” (a statistical note: an equivalency trial is planned from the outset to have a large enough sample to test the hypothesis that, with 95% certainty, the effect of one treatment falls within a narrow, predetermined margin of the effect of another treatment). The study by Driessen and colleagues was conducted in several sites in Amsterdam, in which 341 patients seeking outpatient psychotherapy for depression in psychiatric clinics were randomized to PDT or cognitive behavioural therapy (CBT). This is largest trial ever of PDT. Participants received 16 weeks of therapy and then were followed up for 1 year. About 40% of patients started with severe depression. Therapists were 93 experienced and well trained therapists who provided one of the two treatments. The main outcome was remission from depression, defined by achieving a low score on a validated observer rating scale. Post treatment remission rates were 21% for CBT and 24% for PDT, indicating that the treatments were equivalent.

Practice Implications

Cognitive-behavioral therapy (CBT) and short-term PDT provided similar outcomes for patients with a major depressive episode, but remission rates at the end of treatment were low for both treatments. Lower remission rates were likely due to the greater level of severity for these patients compared to those seen in primary care settings. The results highlight that even the best available psychological (and pharmacological) treatments yield modest outcomes for more severely depressed patients. Nevertheless, this rare equivalency trial found that both CBT and PDT were equivalent in terms of outcomes for these patients.

Author email: e.driessen@vu.nl

Ulvenes, P. G., Berggraf, L., Hoffart, A., Stiles, T. C., Svartberg, M., McCullough, L., & Wampold, B. E. (2012). Different processes for different therapies: Therapist actions, therapeutic bond, and outcome. Psychotherapy, 49(3), 291-302.

One of the few truisms of psychotherapy is that the therapeutic alliance is important to treatment outcomes. But does the alliance work similarly in Cognitive Behavioral Therapy (CBT) and in Psychodynamic Therapy (PDT)? Therapeutic alliance is defined by three elements: the bond between client and therapist, agreement on tasks, and agreement on goals. Compared to PDT therapists, CBT therapists tend to focus more on cognitions and focus less on emotions, and so the bond may be less important in CBT than agreement on tasks and goals. Will the bond between client and therapist be differentially affected by the differing focus on emotions between CBT and PDT? A study by Ulvenes and colleagues (2012) looked at this question. This study is a follow up study of a randomized controlled trial comparing CBT to PDT for the treatment of cluster C personality traits (i.e. individuals who have trouble in experiencing and expressing emotions, and in developing close relationships). Fifty clients were randomized to either CBT or PDT, therapy was short term, and therapists were experienced and competent in delivering their therapy. In the previous study the authors reported that CBT and PDT were both equally effective in treating clients with cluster C personality disorder. In the current study, the authors found that therapist avoidance of affect was associated with developing a greater bond with patients in both CBT and PDT. That is, Cluster C patients liked their therapists better if the therapists avoided talking about the clients’ feelings. However, focusing on affect in PDT was also associated with positive outcome. In other words, therapists who avoided talking about emotions in PDT helped the patient like the therapist better, but this was counterproductive for good outcome. PDT therapists had to manage to create a bond despite their focus on affect in order to achieve good outcomes. On the other hand, focusing on affect in CBT was associated with poorer outcome. That is, therapists who avoided affect in CBT, which is consistent with the treatment model, had clients who experienced both a better bond and better outcomes. Therapeutic alliance is important for all therapies, but may operate quite differently depending on how much the therapy focuses on affect (PDT) or on cognitions (CBT).

Practice Implications

PDT therapists working with cluster C patients have to negotiate a complex task of maintaining a bond despite the treatment model’s focus on emotions in order to achieve good outcomes. CBT therapists will do well to be consistent with the treatment model and focus primarily on cognitions to help with the bond and promote good outcomes. CBT therapists in particular may need to develop a strong bond before agreeing on tasks and goals, which are also keys to a therapeutic alliance.

Author email: pal.ulvenes@modum-bad.no