Document Type



Doctor of Philosophy



Date of Defense


Graduate Advisor

Tara E. Galovski


Kelly Maieritsch

Zoë Peterson

Matthew Taylor


Currently, even well-supported cognitive behavioral therapies to treat posttraumatic stress disorder (PTSD) suffer from consistent rates of dropout and non-response to treatment, which represent barriers to dissemination and effective treatment. Research in anxiety disorders, including an initial group-based study with veterans suffering from PTSD, suggests that Motivational Interviewing (MI) may be an effective intervention for addressing issues of ambivalence and increasing readiness to change (RTC), resulting in decreases in dropout and non-response. The present pilot study sought to assess the efficacy of augmenting Cognitive Processing Therapy (CPT) with 3 sessions of MI in a sample of female interpersonal assault survivors (N = 17). Within the MI study pilot sample, participants presented with a range in RTC, evidenced increases in RTC across the MI sessions (F = 3.48, p = .053), and demonstrated differential need for MI augmentation throughout the CPT sessions, as hypothesized. Moreover, no participants dropped out during the MI sessions, and participants noted that they found the MI sessions helpful and drew on the MI prep sessions to stay motivated during treatment. Contrary to hypotheses, MI did not significantly impact treatment expectations or fear of treatment. The pilot results were also compared to a concurrently conducted comparison CPT trial (N = 92) as well as to the broader PTSD outcomes literature. Interestingly, MI did not have a differential effect on RTC measures (F = 1.86, p = .093) as compared with the comparison study conditions. Comparison results also indicate that MI did not substantially improve dropout rates (χ2 = .49, p = .782) or treatment engagement measures (F = 1.24, p = .290), and that MI+CPT participants evidence similar symptom outcomes to the comparison trial (F = .84, p = .541). Similarly, MI study rates were at the high end for dropout and evidenced equivalent treatment outcomes, as compared to recent CPT trials. Study limitations and clinical implications are considered.

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