Randomized Controlled Trial of Smartphone-Based Interpretation Bias Intervention for Anxiety and Depression

Objective: HabitWorks (HW) is a personalized, transdiagnostic, Smartphone-based interpretation bias intervention for depression and anxiety that has demonstrated feasibility and acceptability in prior pilot studies. This preregistered randomized controlled trial (https://osf.io/7wx9d; Beard et al., 2024) tested the effectiveness of HW compared to a symptom tracking (ST) control condition. Method: U.S. adults with anxiety and depression symptoms (N=340; Mage=33.04 years, 57.4% women, 60.6% White, 14.7% Black, 11.2% Asian, 10.9% Multiracial, 22.1% Hispanic/Latine) were randomly assigned to complete three weekly interpretation bias exercises and once weekly depression and anxiety symptom surveys (HW), or three weekly depression and anxiety symptom surveys (ST) for four weeks. Results: A priori benchmarks for retention, adherence and satisfaction were achieved: 77.8% of HW participants were still using the app in Week 4, 43.7% achieved perfect adherence, and app usability and acceptability were rated positively. As hypothesized, HW was superior to ST at improving negative and benign interpretation biases (Word-Sentence Association Paradigm) and functional impairment (Work and Social Adjustment Scale); and HW (vs. ST) participants also reported significantly greater global improvement (Clinical Global Impressions Scale-Improvement Self-Report) and subjective engagement (Twente Engagement with eHealth Technologies Scale) at post-intervention. Unexpectedly, while depression and anxiety symptoms (Patient Health Questionnaire-8 and Generalized Anxiety Disorder Scale-7) improved significantly, these changes were not unique to the HW condition. Conclusions: HW is an engaging and scalable intervention that may be effective for improving overall severity and functioning, but further validation of effectiveness for specific symptom domains is needed.