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.

A rise in mental illness is expected to follow the COVID-19 pandemic, which has also been projected to lead to a deep global economic recession, further adding to risk factors.

The aim of this review was to assess the impact of the COVID-19 pandemic and previous pandemics, epidemics and economic crises on mental health.

Searches were conducted in PubMed, Web of Science, PsycINFO and Sociological Abstracts. We included studies of all populations exposed to the COVID-19 pandemic, and other similar pandemics/epidemics and economic crises, compared with non-exposed time periods or regions. The outcome was mental health.

The 174 included studies assessed mental health impacts of the COVID-19 pandemic (87 studies), 2008 economic crisis (84 studies) and severe acute respiratory syndrome (SARS) epidemic (three studies). Outcomes were divided into affective disorders, suicides, mental healthcare utilisation and other mental health. COVID-19 pandemic studies were of lesser quality than those for the economic crisis or SARS epidemic. Most studies for all exposures showed increases in affective disorders and other mental health problems. For economic crisis exposure, increases in mental healthcare utilisation and suicides were also found, but these findings were mixed for COVID-19 pandemic exposure. This is probably because of quarantine measures affecting help-seeking and shorter follow-ups of studies of COVID-19 pandemic exposure.

Our findings highlight the importance of available, accessible and sustainable mental health services. Also, socioeconomically disadvantaged populations should be particular targets of policy interventions during the COVID-19 pandemic.

The Helsinki High-Risk Study monitors women treated for schizophrenia-spectrum disorders in Helsinki mental hospitals before 1975, their offspring, and controls.

To compare the development of high-risk and control group children, and investigate which factors predicted future psychiatric disorders.

We examined information from childhood and school health record cards of 159 high-risk and 99 control group offspring. Logistic regression was used to assess whether developmental abnormalities predicted later mental disorders.

Compared with controls, children in the high-risk group had more emotional symptoms before school age, attentional problems and social inhibition at school age, and neurological soft signs throughout. Inthisgroup pre-school socia adjustment problems (OR=9.7, 95% CI 1.8–51.8) or severe neurological symptom: (Fisher's test, P=0.006) predicted future schizophrenia-spectrum disorder. Social adjustment problems and emotional symptoms during school age predicted future non-psychotic psychiatric disorders.

Our study supports the validity of neurological, emotional, social and behavioural markers as vulnerability indicators of psychotic and other mental disorders, particularly among children genetically at high risk of psychosis.

The Helsinki High-Risk Study follows up all women born between 1916 and 1948 and treated for schizophrenia-spectrum disorders in psychiatric hospitals in Helsinki, their offspring born between 1960 and 1964, and controls.

To determine the cumulative incidence of adulthood Axis I disorders among offspring.

Using all hospital and out-patient treatment records we rediagnosed parents and offspring according to DSM– IV-TR criteria. Offspring were grouped by mother's diagnosis (schizophrenia n = 104, schizoaffective disorder n=20, other schizophrenia-spectrum disorder n=30, and affective disorder n=25) and compared with a control group (n = 176). The cumulative incidences of Axis I disorders among offspring were calculated.

The cumulative incidences of any psychotic disorder were 13.5%, 10.0%, 10.0%, 4.0% and 1.1% among offspring of mothers with schizophrenia, schizo-affective disorder, other schizophrenia-spectrum disorders, affective disorders and controls, respectively. The corresponding figures for schizophrenia were 6.7%, 5.0%, 6.7%, 0% and 0.6%, and for any mental disorder 23.1%, 20.0%, 20.0%, 12.0% and 6.9%.

Offspring of mothers with a psychotic disorder have heightened risk of developing a wide range of severe mental disorders.