Suicide is a major public health concern. Identifying those most at risk is vital to ensure the implementation of effective interventions. Mental health (MH) is known to have a genetic component and parental MH is associated with offspring MH. However, little is known about the effect of parental psychopathology on offspring suicide risk. The aim of this study is to determine if children living with parents with poor MH are at an increased risk of poor MH, or death by suicide.

This population-wide cohort study linked data from the 2011 Northern Ireland Census to 6 years' death records (2011–2016). Information on MH status, in addition to other individual and household-level attributes, was derived from the 2011 Census. Logistic regression was utilised to examine the association between parental poor MH and offspring MH and suicide risk, with adjustment for socio-demographic characteristics.

Overall, 11.6% of the cohort of 618 970 individuals were residing with parents who reported poor MH; 1.6% reported poor MH themselves, and 0.04% (n = 260) died by suicide. Living with a parent with poor MH increased the odds of offspring poor MH (OR = 2.80, 95% CI 2.59–3.03). After adjustment for age, gender, physical illness, socio-economic status and own MH, children living with 1 parent with poor MH were 76% more likely to die by suicide compared to children of parents who did not report poor MH (OR = 1.76, 95% CI 1.31–2.36). The effect size increased for children living with 2 parents with poor MH, and was higher in children aged under 24 years.

Living with a parent with poor MH is a significant risk factor for offspring poor MH and suicide, even after adjustment for personal MH status. When treating mental ill-health in parents, potential interventions for their children should also be considered.