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Importance: Previous research indicates that mental disorders may be transmitted from one individual to another within social networks. However, there is a lack of population-based epidemiologic evidence that pertains to the full range of mental disorders., Objective: To examine whether having classmates with a mental disorder diagnosis in the ninth grade of comprehensive school is associated with later risk of being diagnosed with a mental disorder., Design, Setting, and Participants: In a population-based registry study, data on all Finnish citizens born between January 1, 1985, and December 31, 1997, whose demographic, health, and school information were linked from nationwide registers were included. Cohort members were followed up from August 1 in the year they completed ninth grade (approximately aged 16 years) until a diagnosis of mental disorder, emigration, death, or December 31, 2019, whichever occurred first. Data analysis was performed from May 15, 2023, to February 8, 2024., Exposure: The exposure was 1 or more individuals diagnosed with a mental disorder in the same school class in the ninth grade., Main Outcomes and Measures: Being diagnosed with a mental disorder during follow-up., Results: Among the 713 809 cohort members (median age at the start of follow-up, 16.1 [IQR, 15.9-16.4] years; 50.4% were males), 47 433 had a mental disorder diagnosis by the ninth grade. Of the remaining 666 376 cohort members, 167 227 persons (25.1%) received a mental disorder diagnosis during follow-up (7.3 million person-years). A dose-response association was found, with no significant increase in later risk of 1 diagnosed classmate (HR, 1.01; 95% CI, 1.00-1.02), but a 5% increase with more than 1 diagnosed classmate (HR, 1.05; 95% CI, 1.04-1.06). The risk was not proportional over time but was highest during the first year of follow-up, showing a 9% increase for 1 diagnosed classmate (HR, 1.09; 95% CI, 1.04-1.14), and an 18% increase for more than 1 diagnosed classmate (HR, 1.18; 95% CI, 1.13-1.24). Of the examined mental disorders, the risk was greatest for mood, anxiety, and eating disorders. Increased risk was observed after adjusting for an array of parental, school-level, and area-level confounders., Conclusions and Relevance: The findings of this study suggest that mental disorders might be transmitted within adolescent peer networks. More research is required to elucidate the mechanisms underlying the possible transmission of mental disorders.

Background: This study examined the association between early parental death and children's subsequent mental health, years of schooling, and labour-market outcomes (ie, employment and earnings) in adulthood., Methods: We used nationwide register-based data for Finnish citizens born between 1971 and 1986 (n=962 350). Logistic and linear regression models were used to examine the association of early parental death before the age of 21 years with subsequent mental health and labour-market outcomes in adulthood at ages 26-30. The estimated models accounted for an extensive set of demographic and parental characteristics based on longitudinal register data., Results: Early-life parental death was found to be consistently associated with a higher risk of hospitalisation due to mental health disorders, higher use of mental health-related medications, and absence from work due to illness in adulthood. The associations were negative regardless of the gender of the child or parent, but the estimated odds ratios were usually quantitatively larger for males than females. When examining the type of outcome, we observed the largest quantitative effects were observed using substance-use disorders and intentional self-harm as outcomes. Moreover, we documented considerable reductions in years of schooling, employment, and earnings in adulthood., Conclusions: Parental death before the age of 21 was significantly associated with an increased risk of being diagnosed with a mental disorder and lower level of economic well-being measured by labour-market success in adulthood., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

School grades in adolescence have been linked to later psychiatric outcomes, but large-scale nationwide studies across the spectrum of mental disorders are scarce. In the present study, we examined the risk of a wide array of mental disorders in adulthood, as well as the risk of comorbidity, associated with school achievement in adolescence. We used population-based cohort data comprising all individuals born in Finland over the period 1980-2000 (N = 1,070,880) who were followed from age 15 or 16 until a diagnosis of mental disorder, emigration, death, or December 2017, whichever came first. Final grade average from comprehensive school was the exposure, and the first diagnosed mental disorder in a secondary healthcare setting was the outcome. The risks were assessed with Cox proportional hazards models, stratified Cox proportional hazard models within strata of full-siblings, and multinomial regression models. The cumulative incidence of mental disorders was estimated using competing risks regression. Better school achievement was associated with a smaller risk of all subsequent mental disorders and comorbidity, except for eating disorders, where better school achievement was associated with a higher risk. The largest associations were observed between school achievement and substance use disorders. Overall, individuals with school achievement more than two standard deviations below average had an absolute risk of 39.6% of a later mental disorder diagnosis. By contrast, for individuals with school achievement more than two standard deviations above average, the absolute risk of a later mental disorder diagnosis was 15.7%. The results show that the largest mental health burden accumulates among those with the poorest school achievement in adolescence., (© 2023. The Author(s).)

Background: A study was undertaken to examine the association between multiple indicators of socioeconomic position (SEP) at the age of 30 and the subsequent risk of the most common mental disorders., Methods: All persons born in Finland between 1966 and 1986 who were alive and living in Finland at the end of the year when they turned 30 were included. Educational attainment, employment status and personal total income were used as the alternative measures of SEP. Cox proportional hazards models were used to examine the association of SEP at the age of 30 with later risk of mental disorders. Additional analyses were conducted using a sibling design to account for otherwise unobserved shared family characteristics. Competing risks models were used to estimate absolute risks., Results: The study population included 1 268 768 persons, 26% of whom were later diagnosed with a mental disorder. Lower SEP at age 30 was consistently associated with a higher risk of being later diagnosed with a mental disorder, even after accounting for shared family characteristics and prior history of a mental disorder. Diagnosis-specific analyses showed that the associations were considerably stronger when substance misuse or schizophrenia spectrum disorders were used as an outcome. Absolute risk analyses showed that, by the age of 52 years, 58% of persons who had low educational attainment at the age of 30 were later diagnosed with a mental disorder., Conclusions: Poor SEP at the age of 30 is associated with an increased risk of being later diagnosed with a mental disorder., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Objective: To examine the associations between an onset of serious mental disorders before the age of 25 with subsequent employment, income and education outcomes., Methods: Nationwide cohort study including individuals (n = 2 055 720) living in Finland between 1988-2015, who were alive at the end of the year they turned 25. Mental disorder diagnosis between ages 15 and 25 was used as the exposure. The level of education, employment status, annual wage or self-employment earnings, and annual total income between ages 25 and 52 (measurement years 1988-2015) were used as the outcomes., Results: All serious mental disorders were associated with increased risk of not being employed and not having any secondary or higher education between ages 25 and 52. The earnings for individuals with serious mental disorders were considerably low, and the annual median total income remained rather stable between ages 25 and 52 for most of the mental disorder groups., Conclusions: Serious mental disorders are associated with low employment rates and poor educational outcomes, leading to a substantial loss of total earnings over the life course., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)