Statistical analyses
SECONDARY
The statistical package SPSS 23.0 (IBM Corporation Armonk, NY) was used to conduct analysis of covariance to evaluate the main effects of and interactions between experimental group (AT, CON), BDNF genotype (Val/Val carrier, Met carrier), and biological sex (female, male) for the primary (i.e., Trail Making Test) and secondary (i.e., Digit Symbol Substitution Test) outcomes. Baseline Montreal Cognitive Assessment score and baseline score for the outcome variable were entered as covariates in all analysis of covariance models. Analyses were conducted as complete case analyses. Where there was a significant interaction effect, posthoc analyses were then performed using a Bonferroni correction, accounting for the overall correlation between the two measures of executive functions, the Trail Making Test and Digit Symbol Substitution Test. To interpret the three-way interaction of experimental group*BDNF genotype*biological sex, we conducted posthoc comparisons between AT and CON groups in male and female Met carriers and Val/Val carriers separately. Effect sizes for significant results were calculated as partial eta squared (η