Nationwide Mental Health Trends During Pandemic

We conducted a nationwide register-based retrospective surveillance study from 2019 to 2021. Data were gathered from three open-access registers. The number of primary health care visits to physicians due to mental health problems was collected from the Care Register for Primary Health Care, which is maintained by the Finnish Institute of Health and Welfare. The register has excellent coverage, as over 90% of the Finnish primary care centers report data to it [17 ]. Visits with mental health related F category (mental and behavioral disorders) diagnostic codes (International Classification of Diseases 10^th version) were included (Additional file 1: Table S1). Based on these diagnoses, we calculated the yearly incidence per 1000 adolescents and young adults aged 15–24 years in primary care due to mental health problems. The age group is pre-stratified by the Finnish Institute of Health and Welfare (registry owner) for the open-access data. As we defined the inclusion based on the diagnostic code (F-class) we do not have missing information on visit rates. Visits without F-class diagnoses were thus all excluded. One visit may have more than one diagnose, but all of the diagnoses should be relevant to the visit and describe the visit.
In Finland mental health problems are treated in primary care. The patient first meets either a physician or nurse who is specialized to mental health. Prescriptions and medication decisions are made by physicians and similarly sick leave is prescribed physicians only. Severe or treatment persistent cases are referred from primary care to specialized psychiatric healthcare (secondary or tertiary level units with outpatient clinics). Some larger primary care centers have own specialized psychiatrics hired to reduce the need to referrals to specialized healthcare, but these practices have large variations between cities.
In addition, we collected all psychotropic medications prescribed by a physician from the Register of Reimbursable Medicine Costs, which is maintained by the Social Insurance Institution of Finland. Finland has a universal tax-funded health care system, where all medication purchases are reported to the register regardless of the setting of the prescription (primary care, specialized care, hospitals, and private clinics) [18 , 19 (link)]. The register does not, however, contain information on dosage, indication, or for how long the medication was prescribed. Therefore, we calculated the prevalence of medication users per 1000, and labeled persons as users if they purchased medication from the pharmacy. One person might have purchased several different classes of medication. We have included the medications based on the Anatomical Therapeutic Chemical (ATC) Classification system (Additional file 1: Table S2). We analyzed the main classes and the most used medications more specifically. As the register uses default age stratification (which is defined by the register holder), we included medication information for all adolescents aged 13 to 24 years.
Finally, we gathered the population size for each age group from the Population Information System at the end of the year in question and used it as the denominator in the incidence and prevalence calculations [20 ]. Incidence and prevalence were calculated per 1000 persons per age-group with 95% confidence intervals (CI). Incidence comparisons between the pandemic years (2020 and 2021) and the reference year (2019) were made by incidence rate ratios (IRR), and prevalence comparisons were made by prevalence rate ratios (PRR) with CI.
As we used open-access data, no research permissions or ethical committee evaluations were required. All the data generated in this process have been provided as an appendix (Additional file 2: Table S2).