Autism and ADHD traits, effortful control and mental health during the transition from elementary to junior high schools

The transition from elementary to junior high school presents developmental challenges, particularly for students with neurodevelopmental traits. This study examined how autism, attention-deficit/hyperactivity disorder (ADHD) traits and effortful control (EC) were related to changes in mental health during this transition in a large Japanese community sample (N = 2,564). This longitudinal study used data from a community-based cohort of Japanese students and their parents/guardians (N = 2,692). Autism traits were measured using the Autism Spectrum Screening Questionnaire (ASSQ). ADHD traits were assessed with the Attention Deficit/Hyperactivity Disorder Rating Scale (ADHD-RS). Effortful control (EC) was evaluated using the "Effortful Control" subscale of the Early Adolescent Temperament Questionnaire-Revised (EATQ-R). Mental health problems were assessed using the Strengths and Difficulties Questionnaire (SDQ) before and after the transition. Generalized estimating equations (GEE) and latent profile analysis (LPA) were conducted to examine associations among autism and ADHD traits, EC, and mental health across the transition. GEE revealed that higher autism and ADHD traits and lower EC predicted more severe mental health problems. The LPA identified three distinct subgroups characterized by high, moderate, and low SDQ scores across the transition. The high-SDQ group showed elevated autism and ADHD traits and low EC, whereas the low-SDQ group showed low auism and ADHD traits and high EC. The moderate group exhibited intermediate levels for all measures. These findings suggest that pre-existing mental health problems tend to persist during the transition period. Importantly, students with higher autism and ADHD traits and lower EC exhibited diverse adaptation patterns-some improved while others worsened-highlighting that high autism traits are not necessarily associated with post-transition mental health deterioration. This underscores the need for support tailored to neurodevelopmental and self-regulatory profiles.