Intergenerational transmission of mental disorders has been well established, but it is unclear whether exposure to a child's mental disorder increases parents' subsequent risk of mental disorders.

We examined the association of mental disorders in children with their parents' subsequent mental disorders.

In this population-based cohort study, we included all individuals with children born in Finland or Denmark in 1990–2010. Information about mental disorders was acquired from national registers. The follow-up period began when the parent's eldest child was 5 years old (for ICD-10 codes F10–F60) or 1 year old (for codes F70–F98) and ended on 31 December 2019 or when the parent received a mental disorder diagnosis, died, or emigrated from Finland or Denmark. The associations of mental disorders in children with their parents' subsequent mental disorders were examined using Cox proportional hazards models.

The study cohort included 1 651 723 parents. In total, 248 328 women and 250 763 men had at least one child who had been diagnosed with a mental disorder. The risk of a parent receiving a mental disorder diagnosis was higher among those who had a child with a mental disorder compared with those who did not. For both parents, the hazard ratios were greatest in the first 6 months after the child's diagnosis (hazard ratio 2.04–2.54), followed by a subtle decline in the risk (after 2 years, the hazard ratio was 1.33–1.77).

Mental disorders in children are associated with a greater risk of subsequent mental disorders among their parents. Additional support is needed for parents whose children have been recently diagnosed with a mental disorder.

Depression even at the subclinical level is often accompanied by sleep disturbances, but little is known about the dynamics of the sleep stages in relation to depressive symptoms. We examined whether the amount, associations, and transition probabilities of various sleep stages were associated with depressive symptoms in a community sample of adolescents.

The participants (N = 172, 59% girls, mean age 16.9 years) underwent overnight polysomnography and provided data on depressive symptoms (Beck Depression Inventory II). The association between depression status and total duration of each stage type was analyzed using ANOVA and survival analyses. The associations between the number of different sleep stage types were analyzed using graphical Gaussian models, mixed graphical models, and relative importance networks. A Markov chain algorithm was used to estimate the transition probabilities between each state and these probabilities were further compared between depression status groups.

The associations between N1 and N3 were significantly stronger in both directions of the association (p-values for interactions 0.012 and 0.006) in those with more depressive symptoms. Similarly, a stronger association was observed from N1 to wake stage in those with more depressive symptoms (p-value for interaction 0.002). In those with more depressive symptoms, it was more likely to transition from N2 to N3 and from REM to N2 compared to others.

These findings indicate that changes in sleep architecture are not limited to clinical depression and that the transitional dynamics of sleep stages are an important marker of subclinical depression.

Inequality in health and treatment of disease across socioeconomic status groups is a major public health issue.

To examine differences in socioeconomic status in common mental disorders and use of psychotherapy provided by the public and private sector in the UK between 1991 and 2009.

During these years, 28 054 men and women responded to annual surveys by the nationally representative, population-based British Household Panel Survey (on average 7 measurements per participant; 207 545 person-observations). In each year, common mental disorders were assessed with the self-reported 12-item General Health Questionnaire and socioeconomic status was assessed on the basis of household income, occupational status and education.

Higher socioeconomic status was associated with lower odds of common mental disorder (highest v. lowest household income quintile odds ratio (OR) 0.88, 95% CI 0.82–0.94) and of being treated by publicly provided psychotherapy (OR = 0.43, 95% CI 0.34–0.55), but higher odds of being a client of private psychotherapy (OR = 3.33, 95% CI 2.36–4.71). The status difference in publicly provided psychotherapy treatment was more pronounced at the end of follow-up (OR = 0.36, 95% CI 0.23–0.56, in 2005–2009) than at the beginning of the follow-up period (OR =0.96, 95% CI 0.66–1.39, in 1991–1994; time interaction P<0.001). The findings for occupational status and education were similar to those for household income.

The use of publicly provided psychotherapy has improved between 1991 and 2009 among those with low socioeconomic status, although social inequalities in common mental disorders remain.