Novel Cognitive Behavioral Therapy App for Depression in Mild Traumatic Brain Injury: A Randomized Controlled Trial

Background: Depression symptoms following traumatic brain injury (TBI) are common and strongly associated with adverse overall outcomes in military service members, veterans, and civilians. Cognitive behavioral therapy for depression (CBT-D) is considered a first-line treatment for depression symptoms in many contexts. However, costs associated with CBT-D can be substantial, and there are insufficient numbers of providers trained to perform CBT-D. In contradistinction, digital therapeutic interventions such as smartphone apps have virtually unlimited availability and low per-patient costs. However, evidence for efficacy of digital interventions providing CBT-D in the context of TBI is limited. The aims of this study were to design, develop, and test a novel smartphone app to provide CBT-D intended for military service members with depression symptoms and history of mild TBI. Results: We designed a novel smartphone app featuring digital avatar coaches to provide CBT-D intended for military service members with depression symptoms and history of mild TBI. Key features and goals of the 12 weekly CBT lessons included stigma minimization, personal engagement, and 1-2 hours per week of personal challenge homework assignments. We performed a randomized controlled trial initially involving military service members and veterans. Inclusion criteria were later relaxed to allow for civilian participation due to practical constraints . The control group received an app providing educational lessons about concussions and depression which did not include the therapeutic components of CBT. There was no difference between the groups randomized to CBT-D (n=19) vs. educational app control (n=23) in self-reported depression symptoms. Nevertheless, there was a statistically significant benefit of the CBT-D intervention in self-reported insomnia severity at the 16-week follow-up (four weeks post intervention) assessment (Cohens D=0.45, p=0.0064). There were also statistically significant positive correlations (r= 0.46 to 0.76, p=0.046 to 0.001) between changes over time in depression symptoms and changes over time in both insomnia and PTSD symptoms in the CBT-D group. There were no such correlations in the control group. Participants reported higher therapeutic alliance (p=0.0001) and overall mobile application user rating (p=0.036) for the CBT-D app than for the control education app. More favorable therapeutic alliance and mobile application user ratings correlated significantly with greater improvements in depression symptoms in the CBT-D group (r=0.53 to 0.66, p=0.02 to 0.002). However, dropout was substantial (40/59 in the CBT-D group and 31/54 in the control group) and results may not be fully representative of the population at risk. Conclusions: There remains a major unmet need for widely available, low-cost, effective interventions for depression symptoms in the context of mild TBI. The challenges of designing and rigorously assessing the effects such interventions remain formidable. However, the lessons learned from this study and indications of benefit in a highly relevant secondary outcome measure (insomnia) suggest that remote app-based interventions remain therapeutically viable. Trial Registration: clinicaltrials.gov NCT05147506, submitted 20 July 2021, posted 7 December 2021.