Temporal trends and social inequities in adolescent and young adult mental health disorders in Catalonia, Spain: a 2008-2022 primary care cohort study

Background: The prevalence of mental health disorders in children, teens, and young adults is rising at an alarming rate. This study aims to explore time trends in the incidence of mental disorders among young people in Catalonia, Spain from 2008 to 2022, focusing on the effects of the COVID-19 pandemic and from the perspective of social inequities. Methods: A cohort study using primary care records from the SIDIAP database was conducted. It included 2,088,641 individuals aged 10 to 24 years. We examined the incidence of depressive, anxiety, eating, and attention deficit/hyperactivity disorders, stratified by sex, age, deprivation, and nationality. Results: Anxiety disorders were most prevalent in 2022, with an incidence rate (IR) of 2,537 per 100,000 persons-year (95% CI: 2,503-2,571). Depressive disorders followed with an IR of 471 (95% CI: 458-486), ADHD with an IR of 306 (95% CI: 295-317) and eating disorders with an IR of 249 (95% CI: 239-259). All disorders reflected an increasing trend: depressive disorders (IRR: 2.44, 95% CI: 2.31-2.59), anxiety disorders (IRR: 2.33, 95% CI: 2.27-2.39), ADHD (IRR: 2.33, 95%CI: 2.17-2.50), and eating disorders (IRR: 3.29, 95% CI: 3.01-3.59). A significant increase in incidence was observed after the outbreak of the COVID-19 pandemic. Significant associations were reported mainly in girls, in 15-18 years and 19-24 years groups, with high and middle socioeconomic deprivation, and Spanish nationality. Conclusion: The incidence of all studied disorders has steadily increased, reaching unprecedented levels during the pandemic. This increase is not observed uniformly across all axes of social inequity. Understanding these trends is essential for an appropriate healthcare response, while addressing the non-medical determinants, requires action across all sectors of society.