Exposure Therapy May Not Worsen Symptoms in Veterans With Comorbid PTSD, Substance Use Disorder

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The findings of the study challenge concerns that exposure therapy may worsen symptoms in patients with PTSD, particularly when comorbid SUD is present.

Trauma-focused exposure therapy was not found to exacerbate symptoms in veterans with posttraumatic stress disorder (PTSD) and substance use disorder (SUD), according to study data published in Behavioural and Cognitive Psychotherapy. These results support the use of exposure therapy for PTSD, even among those with high symptom severity and comorbid SUD.

Cynthia L Lancaster, PhD, at the University of Nevada, Reno, led study efforts to assess the efficacy of exposure therapy for patients with comorbid PTSD and SUD. Lancaster et al abstracted data from an existing randomized clinical trial of exposure therapy vs relapse prevention among military veterans in the United States. Participants were randomly assigned 2:1 to 12 individual sessions of exposure-based, concurrent treatment of PTSD and SUD (n=49) or nonexposure-based, SUD-only relapse prevention (n=22). The primary outcome was exacerbation of PTSD, SUD, or depression symptoms during treatment, defined as worsening symptoms that exceeded the standard error of the difference between each individual session score.

Dropout rates were high during the trial period, although no between-group differences were observed in the proportion of completers. When considering exacerbation analysis in all enrollees, baseline measures showed no differences between treatment groups.

However, differences emerged when analyses were restricted to those who completed all therapy sessions. Among completers of exposure therapy, 61% (n=17) experienced at least 1 exacerbation of PTSD symptoms and 18% (n=5) met criteria for PTSD at the end of treatment. In the relapse prevention condition, 92% patients experienced at least 1 exacerbation in PTSD symptoms, and 62% met criteria for PTSD at the end of the trial. The researchers reported a trend of patients in the exposure group experiencing fewer exacerbations of PTSD symptoms compared to those in the nonexposure group (t, -2.03; P =.05). As such, exposure therapy was not associated with symptom exacerbation and may even reduce the risk for symptom worsening.

These data challenge concerns that exposure therapy may worsen symptoms in patients with PTSD, particularly when comorbid SUD is present. As study limitations, the investigators cited the small sample size and high dropout rate.

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The investigators noted that “symptom exacerbation may be a phenomenon common to multiple therapeutic approaches” and misattribution of “the cause of exacerbation to the type of psychotherapy,” thus resulting in treatments being “unnecessarily delayed or prematurely terminated,” which could “contribute to overall avoidance behaviour and work against long-term treatment goals.”


Lancaster CL, Gros DF, Mullarkey MC, et al. Does trauma-focused exposure therapy exacerbate symptoms among patients with comorbid PTSD and substance use disorders? Behav Cogn Psychother. 2020;48(1):38-53.