The Efficacy of Acceptance and Commitment Therapy on Self-Stigma Reduction Among People With Mental Illness: A Quasi-Experimental Design

Self-stigma is prevalent and has adverse impact on people with mental illness, including negative effects on self-esteem, help-seeking, quality of life, and personal recovery. This study investigated the efficacy of acceptance and commitment therapy (ACT) in reducing the self-stigma of people with mental illness in a 5-week group intervention. Thirty-six individuals with mental illness were recruited and completed the ACT intervention. The participants from the intervention group were matched by propensity scores on preintervention outcome variables with another 36 individuals with mental illness from the control group. Levels of self-stigma, believability of stigmatizing thoughts, psychological flexibility, and mindfulness were assessed before the intervention, immediately after the intervention, and 1 month after the intervention. Significant interaction effects were found in psychological flexibility and mindfulness, but not self-stigma and believability of stigmatizing thoughts. For the intervention group, time effects were found in selfstigma, believability of stigmatizing thoughts, psychological flexibility, and mindfulness at post- and follow-up assessments. These findings suggested that ACT is potentially effective in improving psychological flexibility and mindfulness. Mediation analyses suggested that psychological flexibility and mindfulness did not mediate changes in self-stigma or the believability of stigmatizing thoughts. Randomized controlled trials are necessary to further determine its effect on self-stigma and selfstigmatizing thought processes.