An investigation of the effect of an acceptance and commitment therapy-based intervention program on university students' aggression tendencies and psychological flexibility

The purpose of this study is to examine the effectiveness of an Acceptance and Commitment Therapy (ACT)–based psychoeducation program designed to reduce aggression tendencies and increase psychological flexibility among university students. A quasi-experimental design with pretest–posttest–follow-up measurements and a control group was employed. The study group for the descriptive analyses consisted of 192 students enrolled in the faculty of education. For the experimental analyses, 17 participants were randomly assigned to the experimental group and 17 to the control group. The experimental group received a 12-session ACT-based intervention program, while no intervention was administered to the control group. The Aggression Tendency Scale and the Multidimensional Psychological Flexibility Inventory were used as data collection tools. Both descriptive and experimental data were analyzed using the SPSS 26.0 statistical package program. Descriptive statistics were used to examine the relationships between the demographic characteristics of the participants and the research variables. Experimental data were analyzed through appropriate parametric and non-parametric tests. The significance level was set at p<.05, and effect sizes were calculated to support the statistical power of the findings. The results revealed a significant decrease in aggression tendencies, a significant increase in psychological flexibility, and a reduction in psychological inflexibility among participants in the experimental group. The effect sizes were large (Cohen's d=–.94; 1.57; r=.76). Follow-up test results indicated that the effects of the program were maintained over time. Correlation analyses demonstrated that psychological flexibility was negatively associated with both aggression tendency and psychological inflexibility. Descriptive findings showed no significant differences in the main variables across class level, socioeconomic status, or parental education level. However, male students exhibited significantly higher levels of aggression tendencythan female students. In addition, students with authoritarian parental attitudes displayed higher aggression tendencies, whereas those with democratic parental attitudes had the lowest levels of aggression. In conclusion, the developed ACT-based psychoeducation program proved to be an effective, powerful, and sustainable intervention for reducing aggression tendencies, increasing psychological flexibility, and decreasing psychological inflexibility among university students. The findings emphasize the importance of implementing preventive and developmental psychoeducational programs to promote mental well-being and non-violent living skills among young adults.