Co-occurring autism spectrum disorder and attention deficit hyperactivity disorder traits are associated with poorer sleep and mental health beyond problematic internet use among health profession students: a cross-sectional analysis

Abstract Background Health professional students with autism spectrum disorder (ASD) and/or attention-deficit/hyperactivity disorder (ADHD) traits may experience poorer sleep and worse mental health. These difficulties are often attributed to problematic internet use, which may obscure underlying trait-related burdens. We examined whether differences in sleep quality and mental health across the trait-defined groups persisted after adjusting for the severity of problematic internet use. Methods We conducted a secondary cross-sectional analysis of questionnaire data from health profession students in Japan ( N = 399). Participants were classified into four groups—typical, ASD only, ADHD only, and co-occurring ASD–ADHD—based on established screening thresholds. Sleep quality, mental health, and problematic internet use were assessed using the Pittsburgh Sleep Quality Index, the 12-item General Health Questionnaire, and the Internet Addiction Test, respectively. Group differences were analyzed using multivariate and univariate general linear models adjusted for age and sex. Results Trait-defined groups differed significantly in the combined outcomes of sleep quality and mental health. This multivariate effect remained significant after adding the Internet Addiction Test score to the model, and no group × Internet Addiction Test interaction was detected. In adjusted comparisons, the co-occurring ASD–ADHD group exhibited the poorest sleep quality and mental health outcomes relative to the typical and single-trait groups, even after controlling for problematic internet use severity. Conclusions Sleep problems and poor mental health associated with ASD and/or ADHD traits, particularly their co-occurrence, persisted after adjustment for problematic internet use. These findings suggest that problematic internet use alone is unlikely to fully account for the observed group differences. Student support should therefore extend beyond device-focused interventions to include neurodevelopmentally informed accommodations and targeted sleep and mental health care.