The effectiveness of character strength intervention on severe mental illness in Hong Kong

The Character Strength Intervention is designed to cultivate and enhance positive traits and virtues in individuals. We sought to explore whether severely mentally ill adult participants who attended sixteen 40-min sessions of the intervention and treatment as usual (TAU) would report higher purpose in life, life satisfaction, recovery, and happiness composite scores than participants in TAU only. Thirty-nine participants received Intervention + TAU, and 50 received TAU-only. The participants filled in the evaluations at baseline, two mid-point assessments during the intervention, and one after the intervention. The ANCOVA models show a significant intervention effect on recovery and happiness at T3 but diminished at T4 after the intervention wrapped up. The intervention group has significantly less deterioration in recovery than the control group. No significant intervention effect emerged in purpose in life and life satisfaction. It should be noted that the intervention outcome is also negatively impacted by the baseline condition. The slope analysis indicates that for intervention recipients whose happiness scores are lower than 14.16, the predicted intervention outcome is even lower than that of the control group. Future severe mental illness interventions could consider incorporating CSI to enhance recovery and happiness while also being mindful of the baseline conditions to enhance intervention efficacy. © 2025 The Authors.