Why adolescents with ADHD take risks : Biological, cognitive and social mechanisms

Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD) demonstrate increased risk-taking behavior (RTB) like substance abuse, delinquency, gambling, sexual RTB and risky traffic conduct. In this dissertation, several biological, cognitive and social mechanisms were hypothesized to contribute to this association. Biologically, the dual-hormone hypothesis (i.e., testosterone is particularly associated with risk taking if cortisol is low) has some potential to explain risk taking, although effects are small and were not observed in relation to ADHD. Furthermore, adolescents demonstrating highest sympathetic reactivity to peer influence were most susceptible to peer influence towards risk taking, although this finding was not exacerbated by ADHD. Cognitively, on gambling tasks, ADHD was consistently associated with suboptimal decision making, as reflected by choosing the option with lowest mean outcome more often. Potentially, this was due the lower complexity of decision-making strategies that were observed in adolescents with ADHD. Socially, risk-encouragement by peers increased subsequent risk taking, but this effect was not specific for ADHD. However, higher levels of ADHD symptoms were consistently associated to lower levels of parental knowledge about their child, and lower parental knowledge was in turn associated with higher levels of RTB. These two social factors were also associated: adolescents reporting higher levels of parental knowledge also reported higher resistance to peer influence. In sum, this dissertation underlines the complex interplay of different mechanisms associated with the link between ADHD and RTB. Clinically, RTB often causes significant impairment in adolescents with ADHD and deserves more attention in assessment and intervention.