Secular trends in mental health problems among young people in Norway: a review and meta-analysis.

There is a growing concern that the mental health of recent generations of youth is deteriorating, yet the etiology of these secular changes is not fully understood. We aimed to review the evidence on trends in mental health problems among young people in Norway. Seven large-scale repeated cross-sectional studies were included in this study, comprising 35 cross-sectional data collections between 1992 and 2019, with a total sample of 776,606 young people. Our study found a clear increase in mental health problems among young females in Norway over the past few decades, while the trends were less marked for males. The proportion of individuals scoring above the problematic symptom score threshold increased on average by 11.2% (range 2.2% to 21.9%) for females and 5.2% (range - 0.9% to 11.1%) for males, based on data from the individual studies. The results from a meta-regression analysis showed that across all surveys, mean symptom scores increased by 17% (95% CI 12 to 21%) among females and 5% (95% CI 1 to 9%) among males from 1992 to 2019. Overall, mental health problems have increased continually since the early 1990s among young people, especially among young females. The cause of these secular changes remains unknown but likely reflect the interplay of several factors at the individual and societal level.Protocol registration: Open science framework, November 8, 2021 ( https://osf.io/g7w3v ).