Digital Monitoring and Chronic Pain Trajectories in Patients Receiving Tertiary Pain Care.

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders that exhibit high comorbidity rates with psychiatric disorders (Hossain et al., ; Larson, Russ, Kahn, & Halfon, ; Simonoff et al., ). Such comorbidities have also been observed in mild cases that do not meet the full diagnostic criteria of these disorders (Kim et al., ; Lundström et al., ; Rai et al., ), indicating that children with subthreshold symptoms often exhibit equivalent clinical support needs (Balázs & Keresztény, ; Kamio et al., ). As mental-health–related problems during school age have long-term effects on educational, occupational, and social functioning in adulthood (Copeland, Wolke, Shanahan, & Costello, ), early intervention is a critical public health priority. However, the specific temporal pathways linking neurodevelopmental disorder traits to secondary mental health problems and the mechanisms for this association remain poorly understood. Moreover, minimal research has been conducted on children with subthreshold symptoms, and their support systems remain underdeveloped. This study addresses this gap by using large-scale longitudinal data from Japanese elementary and middle-school students to examine longitudinal associations between ASD and ADHD traits, social adjustment, and mental health outcomes from childhood through adolescence. By treating neurodevelopmental characteristics as continuous spectra and examining their effects in a nonclinical population, this study aims to inform early intervention strategies and preventive support practices beyond traditional diagnostic frameworks.