Cultural adaptation and feasibility of action over inertia in Japan: a multi-site pilot intervention study.

Introduction: Action Over Inertia (AOI) is a recovery-oriented intervention designed to promote occupational engagement and support personal recovery through changes in everyday activity patterns. While AOI has been examined in Western contexts, its applicability and clinical adaptation in East Asian settings remain underexplored. This study used a mixed-methods approach to examine the feasibility and cultural adaptation of a group-based AOI program in Japan. Methods: A mixed-methods pilot feasibility design was used. The quantitative component was a single-arm repeated-measures pilot study conducted across four psychiatric daycare facilities in Japan. Outcomes were assessed at baseline, post-intervention, and 1-month follow-up in 12 participants with serious mental illness using the Recovery Assessment Scale (RAS), Temple University Community Participation Measure-Japanese version (TUCP-J), and Social Functioning Scale (SFS), alongside symptom severity assessed with the Brief Psychiatric Rating Scale (BPRS). These measures were used as exploratory clinical outcomes to describe preliminary patterns of change and to inform future controlled studies, rather than to determine intervention effectiveness. The qualitative component involved semi-structured interviews with occupational therapists who delivered the intervention, to contextualize the quantitative findings and identify implementation barriers and adaptations. The quantitative intervention study was approved by the Research Ethics Committee of the Graduate School of Medicine, Nagoya University, Japan (2023-0209), and registered with the UMIN Clinical Trials Registry (UMIN000045392). The qualitative interview study was approved by the Ethics Review Committee for Research Involving Human Participants, Nihon Fukushi University, Japan (23-041-03). Results: No significant improvements were observed in the exploratory outcomes of recovery, participation, or social functioning. Although BPRS showed a significant overall time effect, post-hoc comparisons between time points were not significant, and this change cannot be causally attributed to AOI because of the single-arm design. In an exploratory observation, participants with higher symptom severity appeared to show lower community participation. Qualitative findings suggested that the intervention dose, participant-program fit, readiness for activity change, and group-based delivery conditions may need further optimization within Japanese psychiatric daycare settings. Discussion: The findings suggest that group-based AOI may be feasible to implement in Japanese psychiatric daycare settings, but further cultural and clinical adaptation is needed before effectiveness can be evaluated in controlled trials. Adaptation may require preserving AOI's theoretical foundations while making the intervention less exposing, less abstract, and more accessible in group-based settings. Future studies should use controlled designs, longer follow-up periods, and broader outcome indicators to examine the effectiveness and implementation of culturally adapted AOI. Clinical trial registration: UMIN Clinical Trials Registry https://www.umin.ac.jp/ctr/, identifier UMIN000045392.