Validation of a Low-Burden, Once-Daily Obsessive-Compulsive Disorder Measure Over 70 Days: Ecological Momentary Assessment Study.

Background: Ecological momentary assessments (EMAs) are an increasingly popular tool used to measure real-time symptom burden within mental health care, including for obsessive-compulsive disorder (OCD). However, prior studies in the literature have been limited by brief assessment periods, high participant burden, and heterogeneity in both sampling and symptom assessment methodologies. Objective: This study aimed to validate a 12-item EMA questionnaire of OCD symptoms by evaluating its psychometric properties over an extended monitoring period. Methods: Adults with OCD (22/41, 53.7%) and demographically matched healthy controls (19/41, 46.3%) completed up to 70 daily smartphone-delivered EMA surveys assessing the frequency and emotional impact of obsessions and compulsions. Participants with OCD also underwent clinician-administered Yale-Brown Obsessive-Compulsive Scale evaluations at weeks 0, 2, and 10. Results: Our scale demonstrated high internal consistency (Cronbach α=0.96) and convergent validity, with significant correlation with Yale-Brown Obsessive-Compulsive Scale scores at week 2 (ρ=0.59; P=.004) and week 10 (ρ=0.53; P=.01). Participant retention (89.1%) and questionnaire completion rate (89%) were also higher than those seen in the literature (75.2% and 74.2%, respectively). Conclusions: Overall, we provide initial psychometric support for the use of a low-burden EMA tool to capture day-to-day OCD symptom fluctuations over extended periods. Such tools may enhance longitudinal symptom monitoring, improve treatment response tracking, and address limitations inherent in traditional retrospective assessments.