Developing and Testing a Brief Mindfulness Just-in-Time Adaptive Intervention to Reduce Stress Among Caregivers of People With Dementia: Quasi-Experimental Study.

Background: Dementia caregiving entails chronic, fluctuating stress with downstream risks to caregivers' mental health and quality of care. Mindfulness-based interventions can reduce caregiver stress; however, moment-to-moment fluctuations in stress may limit receptivity to practice at any given time. We developed a brief mindfulness just-in-time adaptive intervention (JITAI) that aims to deliver support at the right moment by using machine learning algorithms to optimize notification timing based on receptivity to engage in brief mindfulness practices. Objective: This study aims to evaluate the feasibility, acceptability, and effectiveness of a brief mindfulness JITAI for caregivers of people with dementia on stress, depressive symptoms, caregiver burden, sleep, quality of life, and trait mindfulness. Methods: A single-arm, pretest or posttest design was adopted. A total of 120 community-dwelling caregivers were recruited to participate in the 18-day intervention, which included 4 days of psychoeducation delivered via videos and phone coaching, alongside an in-app brief, low-dose mindfulness-based stress reduction component. From days 5 to 11, prompts were delivered either by a static machine learning model trained on prior pilot data or at random times, with equal probability. From days 12 to 18, three delivery models were used with equal probability, namely static, random, and adaptive models, which updated per participant using accumulating receptivity data. Feasibility and acceptability were assessed post intervention. Standardized measures of stress, depressive symptoms, caregiver burden, positive aspects of caregiving, sleep, quality of life, and trait mindfulness were collected via phone interviews at baseline and post intervention. Results: Retention was 100%. Most participants (111/120, 92.5%) found the app easy to use, 81.7% (98/120) perceived it as helpful for stress management, and 80% (96/120) would recommend it to other caregivers. Pre-post analyses indicated significant reductions in perceived stress (P<.001), depressive symptoms (P<.001), and caregiver burden (P=.003), as well as a significant increase in positive aspects of caregiving (P<.001) and subjective sleep quality (P=.02). Health-related quality of life and trait mindfulness did not change significantly. Conclusions: A brief, smartphone-delivered mindfulness JITAI for caregivers of people with dementia was feasible and acceptable, with high retention and positive user evaluations. Pre-post findings suggest reductions in perceived stress, depressive symptoms, and caregiving burden, alongside increased positive aspects of caregiving and improved sleep, supporting the potential of adaptive, technology-enabled interventions to provide timely support to caregivers.