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Foa, E., McLean, C.P., Zang, Y., Rosenfield, D., Yadin, E… Peterson, A. (2018). Effect of prolonged exposure therapy delivered over 2 weeks vs 8 weeks vs present-centered therapy on PTSD symptom severity in military personnel: A randomized clinical trial. Journal of the American Medical Association, 319, 354-364.

Post-traumatic stress disorder (PTSD) can affect 10% to 20% of military personnel returning from combat. PTSD is often chronic and debilitating, and is associated with symptoms that are distressing, that lower quality of life, and that negatively impact family and loved ones. Prolonged exposure therapy (PE) has been tested in the past, and researchers have claimed that it is an efficacious treatment in civilians and veterans. PE is a form of behavior therapy and cognitive behavioral therapy characterized by re-experiencing the most traumatic event through remembering it and engaging with, rather than avoiding reminders of the trauma. In their treatment guidelines, the American Psychological Association (APA) proposed PE as a recommended treatment for PTSD. In this randomized controlled trial, Foa and colleagues assess if providing PE in intensive short time frame (massed exposure; 10 sessions over 2 weeks) was as effective as standard exposure (10 sessions over 8 weeks) for 370 military personnel in the US with PTSD. That is, the authors were interested to see if providing the same amount of therapy based on exposure in a shorter time was just as effective. They also compared the two versions of PE (massed and standard exposure) to two control conditions: present centred therapy (PCT) that is largely supportive therapy that does not rely on exposure to the trauma, and a no treatment control condition. The main outcomes were reductions in level of PTSD symptoms and reductions in PTSD diagnoses at post-treatment and up to 6 months post-treatment. Massed and standard PE were equally effective in reducing symptoms and diagnoses of PTSD compared to no treatment. However, PE was not more effective than PCT in reducing symptoms and diagnoses, and PCT was more effective than no treatment. Overall, reductions in PTSD symptoms and reduction in PTSD diagnoses were modest. Drop out rates were high at about 50% for all conditions.

Practice Implications

Drop out rates were high and outcomes were modest for these short-term psychological treatments for PTSD in military personnel, such that over 60% still had a diagnosis of PTSD at 6 months follow up. And PE therapy did no better than a control condition (PCT) that simply provided support with no exposure to the trauma. These findings are similar to other research in this area. Psychotherapy for trauma may require more time to work, and perhaps different models of understanding and treating the disorder. As Shedler recently remarked, it takes at least 20 sessions/weeks before 50% of clients improve. So it may not be surprising that 2 or 8 weeks of therapy had only a small impact on PTSD symptoms.

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