This page was translated automatically from Turkish. Read the original

This page is an AI-assisted Turkish summary of the study presented at the 26th World Congress of Psychiatry. The study belongs to the presenting authors; please refer to the original source when citing it.

Institutional variability in ADHD diagnosis across schools and clinics in Norway: a nationwide registry study before, during, and after COVID-19

Institutional variation in adhd diagnosis across schools and clinics in norway: a population-wide registry study before, during, and after covid-19

The increase in ADHD diagnosis rates reflects both a long-term trend and an independent COVID-19-specific effect, with institutional factors at the school and clinic levels accounting for 17.8% of the unexplained variability.

The study aimed to examine whether the increase in attention-deficit/hyperactivity disorder (ADHD) observed in many countries during and after the COVID-19 pandemic represented a pandemic-specific disruption or an intensification of a pre-existing trend, and how educational and clinical systems jointly shape diagnostic trends. Nationwide registry data were linked for approximately 2.79 million enrolled students aged 6 to 13 years, covering 2,805 schools and 123 clinics between 2018 and 2023; data were aggregated at the school, clinic, and year levels. Four-level mixed-effects models were applied to partition the variance in ADHD diagnosis incidence into school, clinic, municipality, and school–clinic interaction levels. ADHD rates increased annually (odds ratio, OR = 1.04; 95% confidence interval, CI 1.01 to 1.07), with an additional increase during the COVID-19 period (OR = 1.34; 95% CI 1.26 to 1.43). Institutional factors accounted for 17.8% of the total unexplained variance; clinics made the largest contribution (7.6%), followed by schools (4.6%) and the school–clinic interaction term (2.7%). Baseline diagnostic variability was greater across clinics than across schools (σ2: 0.27 versus 0.09), whereas COVID-related diagnostic variability was greater across schools than across clinics (σ2: 0.09 versus 0.02); schools with lower baseline diagnosis rates showed more pronounced COVID-related increases (r = -0.63) and temporal increases (r = -0.61). According to the authors, rising ADHD rates reflect both a long-term trend and an independent COVID-19 effect, schools that were low-risk before the pandemic were more strongly affected by it, and institutional differences in risk warrant investigation into explanatory factors at the school and clinic levels.

All WCP 2026 summaries