Many adolescents are brought to the outpatient clinic at Okayama Psychiatric Medical Center for excessive use of the Internet and smartphones. Many of these patients are suspected of having autism spectrum disorder (ASD). Previous studies have reported the association between ASD and excessive use of electronic devices and media, implying that ASD is a risk factor for Internet addiction (IA).
 We conducted a cross-sectional study at Okayama Psychiatric Medical Center to investigate the prevalence of IA among a Japanese adolescent psychiatric clinical cohort with ASD. In the cross-sectional study, 12.9% of the participants were found to have IA. The prevalence was approximately four-times higher than that among the general Japanese adolescent population. This suggests that adolescents with ASD at child and adolescent psychiatry outpatient clinics are a high-risk population for IA.
 Further investigation is warranted to assess the necessity of screening and intervention for IA comorbid with ASD at child and adolescent psychiatry outpatient clinics. We are therefore conducting a 2-year follow-up study to clarify the natural course of IA among adolescents with ASD. The follow-up study will further discussion on the necessity of screening and investigation for IA at child and adolescent psychiatry outpatient clinics.
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