Dorien Bangma

FDM IN ADULTS WITH ADHD | 173 adults with ADHD have more difficulties with the (mental) ability or capacity to make financial decisions and have less knowledge about the execution of relatively simple financial transactions than healthy controls. More specifically, adults with ADHD experienced it as more difficult to identify a financial problem and to consider the risks and benefits of the given problem (i.e., FDMI ‘Identification’ and ‘Understanding’). The results further show that in comparison to healthy controls adults with ADHD have more problems with financial judgment and management and are less capable to find financial support. The mechanisms underlying the problems in financial competence and capacity in adults with ADHD are unclear. Numeracy seems to play a role in financial competence and capacity, which is consistent with previous research (Martin et al., 2012; Niccolai et al., 2017; Sherod et al., 2009) and group differences on these aspects of FDM were found to be mediated by numeracy. However, direct effects of the group differences between adults with ADHD and healthy controls on financial competence and capacity remained significant, which implies that group differences on these measures of FDM cannot be fully explained by difficulties with numeracy of adults with ADHD. Also, adults with ADHD were found to show impairments in vigilance and interference, however, these aspects of cognition did not mediate the group differences on measures of FDM. It is, however, important to keep in mind that not all participants completed the cognitive test battery, resulting in a relatively small sample size for the analyses including standard measures of cognition. Furthermore, the relative conservative p-value used for all analyses may have increased the likelihood of Type II errors and may have masked existing effects. Especially for small effects, the power of our analyses (i.e., 9% for small effects) is problematic and should be considered when interpreting non-significant results. Studies with large sample sizes on the influence of cognition on FDM in adults with ADHD are therefore desirable. The power for medium (i.e., 53%) and large effects (i.e., 94%) are, however, good considering the average power of studies in psychology (Bakker et al., 2012; Cohen, 1962). It is conceivable that the performances of adults with ADHD on financial competence and capacity are the result of motivational deregulation, since both aspects of FDM are considered as relatively basic and simple which is reflected by the high scores obtained by healthy individuals. It is therefore possible that boredom plays a role (Matthies et al., 2012) and may affect task performance adversely. This suggestion is consistent with the finding that adults with ADHD were found to show a decreased temporal discounting compared to healthy controls (i.e., adults with ADHD prefer immediate over delayed rewards, see below). With regard to the use of decision styles, adults with ADHD more often used a spontaneous decision-making style than healthy controls, which corresponds with a stronger tendency of adults with ADHD to buy on impulse which was also found in the present study. These results indicate that adults with ADHD more often have difficulties with suppressing the urge to buy on impulse or to make decisions in a more deliberative manner. Interestingly, adults with ADHD also seem to avoid financial decisions more often than healthy controls. Previous research demonstrated that the use of both the avoidant and spontaneous decision-making style are negatively related to decision-making competence and might be a result of problems with (general) decision-making (Bavol’ár & Orosová, 2015).