The aims of this study were to test the associations of the Internet addiction symptoms with impulsiveness, loneliness, novelty seeking and behavioral inhibition systems among adults with attentiondeficit/hyperactivity disorder (ADHD) and adults with non-ADHD. A total of 146 adults aged between 19 and 33 years involved in this study. Participants were assessed with the Chinese version of the adult ADHD Self-report scale (ASRS), the Revised Chen Internet Addiction Scale (CIAS-R), the Barratt Impulsiveness Scale 11 (BIS-11), the Tridimensional Personality Questionnaire (TPQ), the UCLA loneliness...