BACKGROUND AND OBJECTIVES: We tested feasibility and preliminary benefits of a free mobile app-delivered mindfulness-based intervention for stress among dementia caregivers (i.e., Healthy Minds Program for Caregivers [HMP-C]). RESEARCH DESIGN AND METHODS: Single-blind Stage 1b pilot randomized controlled trial compared 12 weeks of HMP-C (n = 47) with a dose-matched education podcast control (n = 48
Wellness App [WA]). T-tests examined between-group differences. RESULTS: Feasibility benchmarks were met for acceptability (90% eligible enrolled), demand (95% completed post-tests), and data collection (100% measures complete). Treatment satisfaction was sufficient for HMP-C. Adherence was lower than benchmarks (>
52.5 minutes weekly) for HMP-C (57%) and WA (59%). Mechanistic targets of mindfulness (p <
.001
d = -1.21) and positive aspects of caregiving (p <
.001
d = -0.92) showed large pre-post improvements in the HMP-C group. Mechanistic validity was established through significant correlations between change in stress and change in mindfulness (r =-.40, p =.006) and positive aspects of caregiving (r =-.49, p =.001). Pre-post improvements in HMP-C were not statistically significantly compared with WA for stress (p = .097
d = -0.35), depression (p = .110
d = -0.34), or anxiety (p = .237
d = -0.25). DISCUSSION AND IMPLICATIONS: The current study demonstrated feasibility and mechanistic target engagement and validity for HMP-C. As expected in an underpowered feasibility trial, clinical outcomes did not improve more than control, but trends favored HMP-C. Together, findings demonstrate that a fully powered Stage 2 trial is warranted to test the efficacy of HMP-C compared with WA.