# Association of parental education with offspring psychiatric diagnoses, violent crimes, and suicidal behavior: a nationwide Swedish quasi-experimental study

## TL;DR

This study finds that the link between higher parental education and better mental health in children may be due to other factors, not a direct cause.

## Contribution

The study uses a quasi-experimental design to isolate the causal effect of parental education on offspring outcomes.

## Key findings

- Parental education was negatively associated with offspring psychiatric diagnoses, violent crimes, and suicidal behavior.
- After accounting for unmeasured confounding, the effect of parental education on these outcomes was not statistically significant.
- The results suggest that observed associations may reflect unmeasured confounding rather than causal relationships.

## Abstract

Higher parental educational attainment is associated with a reduced risk of mental health problems in offspring. However, these associations might partially reflect unmeasured confounding rather than causal effects.

To investigate the association between parental education and offspring psychiatric diagnoses, violent crimes, and suicidal behavior, after isolating unmeasured confounding.

We analyzed data from 1,047,275 offspring to 701,350 parents born between 1945 and 1955 in 926 Swedish municipalities. The exposure was parental years of schooling. The outcomes were 14 psychiatric diagnoses, court convictions of violent crimes, and suicidal behavior in the offspring. We first estimated the association between parental years of schooling and offspring outcomes using stratified Cox regression. Subsequently, leveraging a Swedish education reform that extended compulsory schooling from 7 to 9 years as a quasi-experiment, we compared parents educated immediately before and after the reform's implementation. This approach allowed us to estimate the reform's impact on offspring outcomes while controlling for potential unmeasured confounders. To estimate the causal effect of the parental education on offspring outcomes, we applied a fuzzy regression discontinuity (RD) design, that is, we used the Swedish education reform as an instrument for parental years of schooling. If the RD model assumptions are met, this design identifies the causal effect of education among those who planned to quit school after completing the minimum compulsory requirement.

Parental years of schooling were negatively associated with most of the 14 psychiatric diagnoses, violent crime, and suicidal behavior in their offspring. However, when comparing children of parents exposed to the reform versus those not exposed, there were no significant differences in these outcomes (e.g., any psychiatric diagnosis: hazard ratio = 1.00, 95% CI 0.99–1.02). Consistently, RD estimates of the effect of parental years of schooling on offspring outcomes were close to the null and not statistically significant after correcting for multiple testing.

Among parents who planned to quit school after completing the minimum compulsory requirement, the negative association between longer years of parental schooling and offspring mental health problems and behavioral outcomes likely reflected unmeasured confounding.

The online version contains supplementary material available at 10.1186/s12916-026-04719-w.