In a recent study published in the JAMA Network Open, researchers examined trends in new attention-deficit/hyperactivity disorder (ADHD) (a neurodevelopmental disorder characterized by persistent inattention, hyperactivity, and impulsivity) diagnoses, prevalence, and ADHD medication use in Finland from 2015 to 2022.
Study: Attention-Deficit/Hyperactivity Disorder Diagnoses in Finland During the COVID-19 Pandemic. Image Credit: ABO PHOTOGRAPHY / Shutterstock
Background
ADHD is linked to various psychiatric disorders and can lead to marginalization from education and the labor market. Global prevalence of ADHD in childhood ranges between 2% to 10%, with higher estimates in interview-based studies. In Finland, adolescent prevalence is around 8.5%, with a lifetime prevalence of 12.6%. Further research is needed to understand the long-term impact of the Coronavirus disease 2019 (COVID-19) pandemic on ADHD prevalence, diagnosis trends, and treatment efficacy.
About the study
The present study assessed new ADHD diagnoses, prevalence, and medication use using nationwide health register data in Finland from January 1, 2015, to June 30, 2022, with diagnoses tracked from January 1969 to June 2022. Ethical approval was granted by the Finnish National Institute for Health and Welfare, and informed consent was not required for anonymized data. The population included all individuals with a Finnish social security number during the study period. ADHD diagnoses were obtained from the National Care Register, and medication data were collected from the National Medicine Purchase Register.
ADHD diagnoses were identified using the International Classification of Diseases (ICD)-8, ICD-9, and ICD-10 codes, and medication data included methylphenidate, atomoxetine, dexamphetamine, and lisdexamphetamine. The primary outcome was the number of new ADHD diagnoses, defined as the first ICD-based diagnosis or medication purchase. Secondary outcomes included ADHD lifetime prevalence and medication use prevalence.
Data were analyzed at three time points: 2015, before the pandemic (April 2019-March 2020), and during the pandemic (July 2021-June 2022). Trend changes were analyzed using age- and sex-specific models. Statistical analyses, performed using R software, involved multivariable Poisson or negative binomial regression. The study followed Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines, and data were analyzed from January 2015 to June 2022.
Study results
The nationwide study cohort comprised 5,572,420 Finland residents. In 2022, the mean age was 44.1 years, and 50.65% were women, with 229,753,086 observed person-years during follow-up.
New ADHD diagnoses doubled from 2015 to the prepandemic year of 2019-2020 in Finland and again doubled from 2019-2020 to the pandemic year of 2021-2022. In 2015, the rate of new ADHD diagnoses per 100,000 was 117. In 2019-2020 it was 238, and in 2022 it was 477. The rate of new ADHD diagnoses was highest among boys younger than 13 years, increasing from 721 per 100,000 in 2015 to 1,745 per 100,000 in 2022. The most significant increase in new ADHD diagnoses was observed among girls and young women aged 13 to 20 years, with a 2.6-fold increase from 577 per 100,000 in 2020 to 1,488 per 100,000 in 2022. Women aged 21 to 30 years experienced a 3.0-fold increase. The rate of new ADHD diagnoses also increased among those older than 55 years, although not significantly exceeding the prepandemic growth trend.
The study estimated the number of incremental new ADHD diagnoses during the pandemic, totaling 9,482 cases, representing 18.60% of all new ADHD diagnoses. Occupational health care joining the Care Register in 2020 may have influenced the rate of new ADHD diagnoses. However, sensitivity analyses excluding these cases showed that the observed incremental increase was not solely attributable to this factor.
Lifetime ADHD prevalence was assessed at three time points. In 2015, it was 1.02%, in 2020 it was 1.80%, and in 2022 it was 2.76%. The number of ADHD cases increased by 43,181 from 2015 to 2020 and by 50,028 during the pandemic from April 2020 to June 2022. Boys and young men aged 13 to 20 years had the highest lifetime ADHD prevalence, reaching 11.68% in 2022. The male-to-female ratio for lifetime ADHD prevalence in 2022 was 1.8:1, with the most significant discrepancy among those aged 0 to 12 years.
The lifetime prevalence of ADHD medication use in 2015 was 0.57%, increasing to 1.15% in March 2020 and 1.69% in June 2022. ADHD medication use was most common among boys younger than 13 and least common among men older than 55. While medication use increased 2.1-fold between 2015 and 2020, the increase was 1.4-fold during the pandemic. The inclusion of occupational health care cases did not significantly change the prevalence of medication use.
Conclusions
To summarize, the findings revealed a twofold increase in new ADHD diagnoses and a 1.5-fold increase in ADHD prevalence during the pandemic compared to the pre-pandemic period. The most significant increases were observed among girls and young women aged 13 to 30 years and individuals over 55. Boys younger than 13 and young men aged 13 to 20 had the highest absolute rates but did not show significant pandemic-related increases. The overall ADHD prevalence was 2.76%, with medication use increasing linearly with new diagnoses, highlighting the pandemic's impact on ADHD recognition. These findings suggest that the increased stress and changes in daily routines during the pandemic may have surfaced previously undiagnosed ADHD cases, revealing the broader implications of how societal disruptions can impact mental health recognition and treatment.
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