Statistical analysis
depression, impulsivity, anxiety
Statistical analyses were performed using SPSS Statistics (version 22.0). Specifically, we performed a frequency analysis of the participants’ sociodemographic characteristics. Although normality was assumed through the normality test, a nonparametric test was performed because the number of study participants was small, and an ordinal scale was used. Ranked ANCOVA was performed for the NK cell count and cortisol levels. The MMPI-2, SAP, EEG, depression, anxiety, and impulsivity data were analyzed using Wilcoxon’s signed rank test. Statistical significance was set at 