Attention-Deficit/Hyperactivity Disorder Diagnoses in Finland During the COVID-19 Pandemic

Importance Several reports suggest an increase in attention-deficit/hyperactivity disorder (ADHD) symptoms during the COVID-19 pandemic. This nationwide study assessed new ADHD diagnoses and ADHD prevalence before and during the pandemic. Objective To investigate trends in new ADHD diagnoses, prevalence, and ADHD medication use from 2015 to 2022 in Finland. Design, Setting, and Participants This longitudinal cohort study comprised the entire Finnish population. ADHD diagnoses and medication use were obtained from nationwide registers and assessed at 3 time points: in 2015 and before (2020) and after (2022) the pandemic. Data were analyzed from January 2015 to June 2022. Main outcomes and Measures New ADHD diagnoses, ADHD lifetime prevalence, and ADHD medication use. Results The cohort comprised 5 572 420 individuals (2 819 645 women 50.6%). Lifetime prevalence of ADHD increased by 2.7-fold during 2015 to 2022; prevalence was 1.02% in 2015 (95% CI, 1.01%-1.03%), 1.80% in 2020 (95% CI, 1.79%-1.81%), and 2.76% in 2022 (95% CI, 2.75%-2.77%). Young men aged 13 to 20 years had the highest lifetime prevalence of 11.68% (95% CI, 11.56%-11.81%) in 2022. New ADHD diagnoses doubled during the pandemic, from 238 per 100 000 in 2020 to 477 per 100 000 in 2022. The pandemic-associated incremental increase in new diagnoses was 18.60% (95% CI, 16.47%-20.49%; 9482 per 50 897 cases). Young women aged 13 to 20 years had a 2.6-fold increase in new diagnoses during the pandemic, from 577 per 100 000 in 2020 to 1488 per 100 000 in 2022, and women aged 21 to 30 years had a 3.0-fold increase, from 361 per 100 000 to 1100 per 100 000. New diagnoses increased by 2.9-fold among those older than 55 years (from 5 per 100 000 to 13 per 100 000 in women and from 5 per 100 000 to 14 per 100 000 in men). Boys younger than 13 years had the highest absolute rate of new ADHD diagnoses in 2022 (1745 per 100 000), but boys and young men younger than 21 years did not show a significant incremental increase in new diagnoses. Lifetime prevalence of ADHD medication purchases was 0.57% (95% CI, 0.56%-0.58%) in 2015 (31 771 55.62% of those with ADHD diagnosis), 1.15% (95% CI, 1.14%-1.16%) in 2020 (64 034 63.83%), and 1.69% (95% CI 1.68%-1.70%) in 2022 (92 557 61.43%), respectively. Conclusions and Relevance In this nationwide cohort study, new ADHD diagnoses and ADHD prevalence showed significant increase in Finland during the pandemic. ADHD medication use did not increase in relation to ADHD diagnoses. These results highlight potential adverse outcomes of pandemic-associated changes in living conditions.