Background and Aims: Problematic Internet Use (PIU) is commonplace but is not yet recognized as a formal mental disorder. Excessive Internet use could result from other conditions such as gambling disorder. The aim of the study was to assess the impact of impulsive-compulsive comorbidities on the presentation of PIU, defined using Young’s Diagnostic Questionnaire.

Methods: 123 adults aged 18-29 years were recruited using media advertisements, and attended the research center for a detailed psychiatric assessment, including interviews, completion of questionnaires and neuropsychological testing. Participants were classified into three groups: PIU with no comorbid impulsive/compulsive disorders (n=18), PIU with one or more comorbid impulsive/compulsive disorders (n=37), and healthy controls (n=67). Differences between the three groups were characterized in terms of demographic, clinical, and cognitive variables. Effect sizes for overall effects of group were also reported.

Results: The three groups did not differ significantly on age, gender, levels of education, nicotine consumption, or alcohol use (small effect sizes). Quality of life was significantly impaired in PIU irrespective of whether or not individuals had comorbid impulsive/compulsive disorders (large effect size). However, impaired response inhibition and decision-making were only identified in PIU with impulsive/compulsive comorbidities (medium effect sizes).