Dorien Bangma

174 | CHAPTER 7 Adults with ADHD also showed more difficulties with making financial decisions that have implications for the future compared to healthy controls. This means that adults with ADHD discounted the value of money that they could receive later in time (i.e., temporal discounting) stronger than healthy controls. The effect of temporal discounting has been frequently described in children and adolescents with ADHD (Barkley et al., 2001; Demurie et al., 2012; Scheres et al., 2013) and was attributed to a motivational deregulation or self-control problem (Scheres et al., 2013). However, research on temporal discounting of adults with ADHD is limited and results are inconsistent (see Mowinckel et al. (2015) for recent meta- analysis). This inconsistency may be the result of third variables that are likely to interact with someone’s temporal discounting tendency, such as income or financial reserves (Green et al., 1996). No differences were found between adults with ADHD and healthy controls regarding emotional decision making (i.e., IGT) and the ability to apply decision-rules in financial situations (i.e., CDR). These findings are in contrast with Mäntylä et al. (2012) who observed that adults with ADHD have difficulties with applying decision-rules. This inconsistency may be explained by the fact that the participants in our study received on average 5 years of education more than the participants in the study of Mäntylä et al. (2012) and the finding that years of education seems to be a significant predictor of the ability to apply decision-rules (Bangma et al., 2017). Inconsistent results are also found by previous studies that applied the IGT in adults with ADHD (Groen et al., 2013; Mowinckel et al., 2015). In the present study, no difference was found between healthy controls and adults with ADHD on this measure of emotional decision-making. Therefore, the present data adds evidence suggesting that adults with ADHD have no pronounced problems in risky or emotional decision-making. However, in this context third variables such as level of education might also play a role (Davis et al., 2008; Fry et al., 2009). Furthermore, the latter result appears to be in contrast with the difference found between adults with ADHD and healthy controls regarding temporal discounting, as it has been suggested that a preference for immediate over delayed rewards (i.e., a decreased temporal discounting) would result in increased risky behavior (Groen et al., 2013; Sonuga- Barke, 2003). A recent study in children with ADHD, however, indicates that the tendency to choose the least delayed option does not result in increased risk taking. Instead, children with ADHD were found to have more difficulties with adjustment in relation to changing risk probabilities than healthy controls (Sørensen et al., 2017), probabilities that do not change during the IGT that was used in the present study. When interpreting the results of the present study, some limitations need to be taken into account. First, in the present sample, 19 adults with ADHD with comorbid disorder(s) of which three with substance dependency were included. These comorbid disorders may be relevant with regard to the differences found between adults with ADHD and healthy controls. Additional analyses excluding the adults with ADHD with substance dependency (n = 3 excluded, data of additional analyses not reported) replicated the results with regard to the objective measures of FDM. Also when excluding all adults with ADHD with comorbid disorders (n = 19), largely similar results were found (data not reported). Only the difference between adults with ADHD and healthy controls for IBQ total score was no longer significant