Abstract
IMPORTANCE: Individuals with intellectual disabilities (IDs) are at increased risk for mental health problems, including depression. However, access to effective therapeutic interventions is often limited. OBJECTIVE: To evaluate the feasibility, acceptance, and efficacy of a self-help smartphone app designed to reduce depressive symptoms and improve self-esteem and quality of life in individuals with IDs. DESIGN, SETTING, AND PARTICIPANTS: In this 2-arm randomized clinical trial, adults with IDs and depressive symptoms were enrolled online in Germany between April 1 and August 10, 2023. Of the 135 individuals who accessed the survey, 99 met the eligibility criteria. Participants were recruited via social media, third parties (eg, care institutions), and workplaces. Data were collected at baseline and after the intervention. Statistical analyses included complete case and intention-to-treat (ITT) approaches. INTERVENTION: Participants were randomly assigned (1:1) to either the intervention group using a smartphone app in easy-to-read German mainly on cognitive behavioral therapy or a waiting list control group. Participants in both groups continued to receive care as usual, which may include routine psychosocial support, daily structure provided by caregivers, and access to general health services. MAIN OUTCOMES AND MEASURES: The primary outcome was a reduction in depressive symptoms, measured by the Glasgow Depression Scale for People With a Learning Disability. Secondary outcomes were improvements in self-esteem, quality of life, and participant satisfaction. RESULTS: Among the 99 participants (mean [SD] age, 34.9 [12.6] years; 54 [54.5%] female), 92 completed the postintervention assessment. The intervention group showed a significant reduction in depressive symptoms compared with the control group in ITT analyses (F1,97 = 7.52; P = .007; ηp2 = 0.072; medium effect size), as well as significant improvements in quality of life (F1,97 = 5.09; P = .03; ηp2 = 0.050; small to medium effect size) and in self-esteem (F1,97 = 17.94; P < .001; ηp2 = 0.156; large effect size). Complete case analyses yielded consistent results on most outcome measures. High satisfaction ratings were reported. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, a self-guided smartphone app demonstrated efficacy in reducing depressive symptoms and enhancing quality of life and self-esteem among individuals with IDs. The findings suggest that smartphone-based interventions can provide effective support for this underserved population. TRIAL REGISTRATION: German Clinical Trials Register Identifier: DRKS00030858.