Do people with ADHD run more risks?
If I offer you 100€ now or 500€ next month, what would you choose? Most people would probably choose the offer after one month, but research has demonstrated that people with Attention Deficit Hyperactivity Disorder (ADHD) are likely to go for the immediate reward. It has very consistently been shown that people with ADHD in general have a preference for immediate over delayed rewards: they are considered ‘delay averse’. In everyday life they therefore value short-term pleasure more, e.g. going to a party instead of preparing for an exam, and are less likely to consider long-term outcomes, e.g. passing the exam, getting a degree. The delay aversion in ADHD can be explained by a dysfunction in the brain’s reward system, which causes this type of motivational problems.
In addition to delay aversion, there is ample evidence that people with ADHD run more risks in everyday life. For example, on average they drive more dangerously and are more often involved in traffic accidents. Other examples are that they are more engaged in risky sexual and criminal behaviour. Increased risk behaviour cannot be solely explained by delay aversion, because the likelihood of the rewards is not taken into account. As people with ADHD make more risky choices in everyday life, they might favour less likely larger rewards over more likely smaller rewards.
“We tested this by systematically reviewing the international scientific literature on the performance of people with ADHD in gambling tasks and expected that people with ADHD would run more risks when playing gambling tasks than people without ADHD.”
In neuropsychology, gambling tasks are often used to objectively determine how people make decisions. In these tasks participants can usually choose between several options that differ in the likelihood for receiving a reward or penalty. The likelihood for obtaining a reward or penalty is called the probability. The exact probability of the outcome can be evident for the participant (explicit) or not (implicit). For example, when throwing a die you know exactly that the chance for throwing a 6 is 1/6th, which makes this an explicit gamble. However, when for example pumping a balloon, you cannot rationally calculate when it is going to burst. You need experience with previous balloons to get a feeling when it will burst, which makes pumping a balloon an implicit gamble. Therefore implicit gambling relies more on emotional and affective responses of the brain, whereas explicit gambling relies more on rational processes in the brain. Although all theoretical models of ADHD predict more risky choices, they predict different outcomes for implicit and explicit gambling tasks. Some say that only implicit gambling would be more risky in ADHD, whereas others say that both types of gambling would be more risky.
“The outcomes were not what we expected.”
Only half of the studies looking at children/adolescents with ADHD (7 out of 14 studies) found evidence that they run more risks on gambling tasks. And only a minority of the studies on adults with ADHD (3 out of 11 studies) reported increased risky behaviour on gambling tasks. Importantly, it did not matter whether implicit or explicit gambling tasks were investigated; the results were similar for both types of tasks. This outcome challenges motivational models of ADHD as well as the common sense idea that people with ADHD favour less likely larger rewards over more likely smaller rewards.
“We weren’t scientists if we would not try to discover what causes this unexpected outcome.”
Three possible factors were investigated: Firstly, two studies provided evidence that children with ADHD who also had oppositional defiant disorder (ODD) or conduct disorder (CD) had increased risky behaviour in gambling tasks. These disorders are often seen together with ADHD and such children present an ongoing pattern of anger-guided disobedience, hostility, and defiant behaviour toward authority figures (that in case of CD violate societal rules or norms). It could be that not ADHD itself but ODD/CD is associated with risky behaviour on gambling tasks. Secondly, about 2/3rd of the studies included small samples of people with ADHD (less than 30 people per group). This reduces the chance of finding true differences between people with and without ADHD. If larger samples would have been used in every study, this could have resulted in the expected outcomes. Thirdly, the tasks that were used to measure risk taking may not be a good reflection of actual risk taking in everyday life. For most of the used gambling tasks it is unknown how gambling performance is connected to daily life risk taking behaviour, in particular in children.
Concluding, although weaknesses of the reviewed studies may have affected the results, the presumption that people with ADHD run more risks on gambling tasks may not be true. This finding is contradictory to the everyday life examples of risky behaviour in ADHD and challenges motivational models of ADHD.