Japanese study reveals greater ADHD mental health burden in girls

A large Japanese survey found that children diagnosed with attention-deficit/hyperactivity disorder had substantially more depression, anxiety, irritability, bullying victimization and academic difficulties than peers without ADHD, with girls showing larger differences than boys in several mental health measures. The comparative cross-sectional study included 1,594 children aged 6–18 and their parents: 797 with a formal ADHD diagnosis and 797 without one. Across elementary, junior high and senior high school, most ADHD-related differences were moderate to very large, although perceived teacher support was the principal exception.

Parents completed an online questionnaire about their oldest eligible child, covering ADHD symptoms, depressive symptoms, anxiety across six domains, irritability, bullying, academic performance and support from friends and teachers. The ADHD Rating Scale-IV, Short Mood and Feelings Questionnaire, Spence Children’s Anxiety Scale and Affective Reactivity Index produced mean symptom scores that were markedly higher in the ADHD group. Mean depression scores were 6.55 versus 1.87, total anxiety scores were 23.20 versus 8.25, and irritability scores were 3.75 versus 0.89. The corresponding overall effect sizes were Cohen’s d = 0.93 for depression, 0.80 for anxiety and 1.04 for irritability.

School-related outcomes also differed. Among children with ADHD, 31.0% experienced some form of bullying during the previous two months, compared with 7.5% of children without ADHD. The researchers also found that 53.0% of the ADHD group performed in the bottom 60% of parent-rated academic achievement, compared with 18.7% of the comparison group. Friend support was less common in the ADHD group, while teacher support produced a much smaller and statistically nonsignificant difference in the three-way analysis. Three-way analyses of variance tested ADHD status, child sex and educational stage together, and standardized mean differences were calculated separately for each stage and sex.

The clearest sex pattern involved emotional and social symptoms. Across the three educational stages, girls with ADHD had larger ADHD–non-ADHD differences than boys for depression, with a mean effect size of 1.14 versus 0.84; anxiety, 1.13 versus 0.73; and irritability, 1.32 versus 0.90. Significant ADHD-by-sex interactions were detected for depression, anxiety, irritability and bullying victimization. Girls also had larger bullying-related effect sizes at every stage: 1.06 versus 0.55 in elementary school, 0.62 versus 0.35 in junior high school and 0.75 versus 0.37 in senior high school. These results describe differences between groups, not evidence that ADHD caused the reported outcomes.

Educational stage produced a more varied pattern. Among girls, the largest depression difference appeared in elementary school, with Cohen’s d = 1.41, rather than junior high school, where it was 0.99; the senior high school value was 1.00. Girls’ anxiety differences were similarly large in elementary and junior high school, at 1.25 and 1.30, before falling to 0.82 in senior high school. For boys, anxiety differences ranged from 0.63 to 0.84. Bullying-related differences were largest in elementary school and generally smaller in later stages. Academic differences followed another trajectory, rising particularly for boys from d = 0.65 in elementary school to 1.07 in junior high school, then falling to 0.38 in senior high school.

Analysis within the ADHD group indicated that the two main symptom dimensions had different statistical associations with outcomes. Hyperactivity and impulsivity were the stronger correlates of emotional and social difficulties, including separation anxiety, panic or agoraphobia, generalized anxiety, irritability and depression. The largest corresponding standardized regression coefficients ranged from 0.32 to 0.60, and these models explained 10%–31% of the variance in mental health outcomes. Inattention was most strongly associated with poorer academic performance, with a standardized coefficient of −0.51. It also showed smaller associations with depression and irritability. These are adjusted associations within a cross-sectional dataset and do not establish temporal or causal relationships.

Because the diagnosed group had a lower reported household income, the researchers repeated analyses with income as a covariate. The principal ADHD effects and the ADHD-by-sex interactions remained after this adjustment. Income was associated with academic achievement and with a small number of anxiety outcomes, but not with depression, irritability, bullying, friend support or teacher support. These sensitivity analyses reduce concern that the main group differences were solely explained by the income imbalance, although they cannot address other sources of confounding. The groups also differed in age, respondent sex, child sex, residence and the distribution of children across school stages.

The findings have important boundaries. ADHD diagnoses were reported by parents rather than independently verified, and the survey did not record when diagnoses occurred or whether children remained symptomatic. It also lacked individual information about autism spectrum disorder, learning disabilities, treatment and parental education. Comorbid conditions may therefore contribute to some bullying and academic differences. The cross-sectional design cannot show that symptoms worsened as children progressed through school, and apparent stage differences could reflect age-related measurement, cohort effects, selection into particular school tracks or other confounding. The online panel may also underrepresent families with limited internet access. Parent reports may become less sensitive to depression and anxiety as adolescents spend more time away from home and become less emotionally observable to caregivers.

Overall, the study portrays ADHD in Japan as associated with broad difficulties that begin in elementary school and extend through the secondary years, but whose form differs by domain. The results provide evidence for disproportionate emotional and bullying-related burdens among girls, alongside a cross-sectional pattern linking inattention more closely with academic impairment and hyperactivity or impulsivity more closely with internalizing symptoms. They also show why apparent improvements in parent-reported symptoms during adolescence should be interpreted cautiously. Future work following the same children longitudinally, using child self-reports and teacher assessments alongside parent reports and checking diagnoses and coexisting conditions, would be needed to determine which patterns reflect genuine developmental change and which are hidden by the study’s measurement and design.

Subject of Research: Sex- and school-stage differences in mental health and school impairments associated with ADHD among Japanese youth

Article Title: ADHD-related mental health and school impairments across educational stages: sex-specific patterns in Japanese youth

Article References: Takahashi, F. (2026). ADHD-related mental health and school impairments across educational stages: sex-specific patterns in Japanese youth. Frontiers in Psychiatry, 17, Article 1736727. https://doi.org/10.3389/fpsyt.2026.1736727

Image Credits: AI Generated

DOI: 10.3389/fpsyt.2026.1736727

Keywords: ADHD, Japanese youth, mental health, sex differences, school impairment, bullying, depression, anxiety, irritability, academic achievement, ADHD-related, mental