Statistical Analysis
Statistical analysis was performed using the software program IBM Statistical Package for Social Sciences (SPSS) 27 for Windows. A comparison of demographic data and research-related variables at the pretest between the psychoeducation and HRV-BF groups was performed with F tests and chi-square tests to determine the equivalence of the groups. For neuropsychological and physiological measures, two-factor ANOVAs were used to analyze the interaction effect of groups (psychoeducation and HRV-BF groups) x time (pretest and posttest). The effect size was determined by partial eta squared (