A longitudinal study published in Psychological Medicine suggests that social difficulties in school and with family do not simply follow autism or ADHD traits in a straight line. Instead, day-to-day social struggles and mental health challenges appear to be linked in bidirectional, self-reinforcing cycles as children grow older.
The research tracked 9,619 students from public elementary and junior high schools in a medium-sized municipality in central Japan, surveying each child once per school year from fourth through ninth grade. Data were collected from students, their parents and homeroom teachers over 11 grade cohorts between 2012 and 2023.
Autistic traits were found to have consistent, time-ordered links with later peer difficulties, with standardized coefficients ranging from 0.146 to 0.190—well within what researchers classify as large effects. They were also associated with later internalizing problems, though the coefficients were smaller, between 0.068 and 0.097. By contrast, autistic traits did not show a consistent relationship with subsequent academic struggles or conflicts with teachers.
In contrast, ADHD traits displayed a different trajectory. Elevated ADHD traits were linked to later externalizing problems, with coefficients from 0.064 to 0.118, the strongest connections appearing in late elementary years. ADHD traits also predicted higher levels of academic difficulty over time, particularly in fourth and fifth grade, but showed only weak and inconsistent direct links to later internalizing problems. When internalizing symptoms did arise, they tended to be driven by academic difficulties rather than a direct effect of attention problems.
The study highlighted bidirectional processes. Peer problems predicted increases in subsequent internalizing symptoms, while higher internalizing symptoms were also associated with worsening peer problems over time. Externalizing behaviours forecast more frequent conflicts with teachers and parents in later years, and those strained relationships were linked with subsequent rises in behavioural problems. Academic problems consistently predicted greater family conflict in the following year, with coefficients ranging from 0.105 to 0.163.
The social environment also appeared to shape how parents perceived neurodevelopmental traits. Experiencing peer problems was linked to higher reported autistic traits in later grades, with coefficients up to 0.164. Similarly, higher levels of externalising behaviours predicted increased reporting of ADHD traits in subsequent waves.
“One important message is that ASD and ADHD traits showed different patterns of association with later difficulties,” Hashimoto noted. “These findings highlight the importance of considering not only children’s individual characteristics but also the social environments in which they develop.”
The researchers emphasised that the study does not prove causality. “This study does not demonstrate causality,” Hashimoto said. “The findings show temporal associations, not proof that one factor directly causes another.” She also stressed that children with elevated ASD or ADHD traits are highly diverse and that the results describe group-level patterns rather than predictions for any individual child. “In addition, we examined ASD and ADHD traits dimensionally in a general school population rather than focusing specifically on children with clinical diagnoses.”
Several caveats accompany the findings. Many associations, including most links between the traits and later mental health problems, were small to medium in size. The autism measure used captured a relatively narrow set of characteristics, focusing largely on Asperger-type social and behavioural traits rather than the full spectrum.
Looking ahead, the authors suggest that future research include direct observational measures alongside questionnaires and explore whether supportive social settings can buffer these links. They note that early help with academic organisation, peer relationship skills and positive communication between families and schools might help interrupt these cycles, though the study did not test any interventions.
The study, “Longitudinal associations among autism and ADHD traits, social maladjustment, and mental health in school-aged children,” was authored by Eriko Hashimoto, Hiroyuki Ito, Megumi Hamada, Takahiro Nakajima, Nobuya Takayanagi, Mitsunori Myogan, Yasuo Murayama, and Masatsugu Tsujii.
