Cognitive Training via a Mobile Application to Reduce Obsessive-Compulsive-Related Distress and Cognitions During the COVID-19 Outbreaks: A Randomized Controlled Trial Using a Subclinical Cohort

•GG OCD is a mobile app designed to challenge maladaptive OCD-related beliefs.•A randomized controlled trial was carried out to investigate the efficacy of GG OCD.•12 days of daily GG OCD use led to reductions in OCD-related beliefs and symptoms.•Reductions in maladaptive beliefs and OCD symptoms were maintained at follow-up.•GG OCD may be a useful self-help intervention tool during the times of pandemic. Obsessive-compulsive disorder (OCD) is a persistent psychiatric disorder causing significant impairment in functioning. The COVID-19 pandemic has exacerbated OCD-related symptoms and interrupted access to treatment. Recent research suggests mHealth apps are promising tools for coping with OCD symptoms. This randomized controlled trial evaluated the effects of a CBT-based mobile application designed to reduce OCD symptoms and cognitions in community participants considered at high risk of developing OCD symptoms. Following initial screening (n = 924), fifty-five community participants scoring 2 standard deviations above the OCI-R mean were randomized into two groups. In the immediate-app use group (iApp; n = 25), participants started using the application at baseline (T0), 4 min a day, for 12 days (T0–T1). Participants in the delayed-app group (dApp; n = 20) started using the mobile application at T1 (crossover) and used the app for the following 12 consecutive days (T1–T2). Intention to treat analyses indicated that using the app for 12 consecutive days was associated with large effect-size reductions (Cohen’s d ranging from .87 to 2.73) in OCD symptoms and maladaptive cognitions in the iApp group (from T0 to T1) and dApp group (from T1 to T2). These reductions were maintained at follow-up. Our findings underscore the usefulness of brief, low-intensity, portable interventions in reducing OCD symptoms and cognitions during the pandemic.