Motivational but not executive dysfunction in attention deficit/hyperactivity disorder predicts internet addiction: Evidence from a longitudinal study.

• The causal priority between ADHD and internet addiction among young adults was tested across a six-month interval. • ADHD symptoms predicted internet addiction severity but not vice versa. • Three subtypes of dysfunction in ADHD were distinguished by cognitive tasks. • Motivational dysfunction in ADHD is a better predictor of internet addiction than executive dysfunction. This study tested the causal link between Attention Deficit/Hyperactivity Disorder (ADHD) and Internet addiction (IA) and investigated motivational and executive dysfunction as explanatory mechanisms in this association. A sample of 682 young adults completed self-report measures both at Time1 and Time2, six-months apart, including 54 ADHD participants diagnosed by the Conners' Adult ADHD Rating Scale and the Continuous Performance Test. According to the performance in four cognitive tasks, ADHD participants were classified into three groups based on the dual pathway model of ADHD: executive dysfunction (ED), motivational dysfunction (MD) and combined dysfunction (CD). Participants' severity of IA symptoms was assessed using the self-report Chen IA Scale. Results indicated that ADHD scores at Time1 predicted IA scores at Time2 but not vice versa. ADHD participants were easier to be IA than controls, while the severity of IA among the three ADHD groups changed differently. The MD and CD groups became more excessively engaged in Internet use over the course of the six-months while the ED group was unchanged. These findings identify ADHD as a potential risk factor for IA and suggest that motivational dysfunction, characterized by an excessive preference for immediate reward over delayed rewards, is a better predictor of IA than executive dysfunction. [ABSTRACT FROM AUTHOR]