Feasibility Study of a Novel App-Based Anxiety Intervention for Autistic People.

At least 50% of autistic people experience clinically relevant anxiety symptoms. However, reasons for elevated rates of anxiety in autism remain poorly understood and there is a high unmet need for novel and adapted therapies for anxiety that are accessible to autistic people. This study aimed to establish the feasibility of a novel app-based anxiety management tool ("Molehill Mountain") that has been developed with, and adapted for, autistic people. A single-centre, single-arm feasibility study design was employed, whereby autistic people (≥ 16 years) with mild-to-severe symptoms of anxiety were recruited to a 13-week intervention period (King's College London, UK; clinicaltrials.gov identifier NCT05302167). Of 123 prospective participants screened, 100 (81%) participants aged 16-74 years (n = 69 female) were enrolled within approximately 15 months. n = 76 (76%) completed an anxiety measure at ~15 weeks (Generalized Anxiety Disorder-7 Item Scale; GAD-7). Most adhered to the full intervention duration: 65% (n = 47), with most using the app weekly (1-6 days per week; 58%). 73% of participants agreed that they found the app easy to use overall and that an app is a good format for offering anxiety support to autistic people. There was a significant reduction in self-reported anxiety symptom severity with mean difference 2.88 (95% CI 1.88, 3.89; p < 0.001; Cohen's d = 0.45). We found that an autism-adapted app-based anxiety management tool is acceptable to the community and associated with reduced anxiety symptom severity in autistic adults, on average. Following optimization to further enhance usability, the efficacy of the Molehill Mountain app for reducing anxiety must now be tested under randomized controlled conditions in a full-scale clinical trial.