Dorien Bangma

166 | CHAPTER 7 FDM tests (i.e., total scores) were categorized using cut-off scores relative to the mean performance and standard deviation (SD) of healthy controls. Scores were classified as normal if scores were less than 1.5 SD below the mean. Scores were classified as low if scores were between 1.5 and 2.0 SD below the mean and as very low/impaired if the scores were more than 2.0 SD below the mean. Cognition and FDM. To determine to what extent cognition influenced the performances of adults with ADHD (n = 27) and healthy controls (n = 50) on measures of FDM, bootstrapped mediation regression analyses (1000 random samples) were performed, using PROCESS version 3.0 (Hayes, 2013) for those measures of FDMwhich show significant group differences between adults with ADHD and healthy controls. Measures of cognition on which adults with ADHD showed significantly lower performances compared to healthy controls were included as mediation variables. A mediation effect of cognition is indicated when cognition is found to have a significant influence on the difference between adults with ADHD and healthy controls regarding FDM (path ab; Figure 7.1). Results Cognitive performance Compared to healthy controls, adults with ADHD showed significantly lower scores (medium effect sizes) on measures of Vigilance (WAFV reaction time; t = -2.85, p = .006, d = 0.68), Interference (STROOP interference; t = -2.98, p = .005, d = 0.77) and Numeracy (WAIS-IV Arithmetic accuracy; t = 2.84, p = .006, d = 0.57). No significant group differences were found for the other measures of cognition (Appendix 7-1). Personal financial situation On five out of nine aspects of personal finances statistically significant group differences between adults with ADHD and healthy controls were found (Table 7.2). The median income Direct effect (path c’) and indirect effect (path ab). Measures of cognition path a path b Adults with ADHD vs. Healthy controls Measures of FDM path c’ Figure 7.1. Schematic overview of the hypothesized mediating effect of cognition on the difference between adults with ADHD and healthy controls regarding FDM.