Mother's and Father's Serious Mental Illness and Risk of Child Injury in a Taiwanese Birth Cohort

Parental serious mental illness (SMI) is associated with childhood injury. This study investigated whether child injury risk differs according to which parent is affected, SMI diagnosis, or timing of SMI onset.

This cohort study included 1,999,322 singletons born in 2004-2014 identified from the national Taiwanese registries. General estimating equation Poisson models were used to estimate incidence rate ratios (IRRs) of injury events and hospitalizations before the age of 5 years among children according to which parent was affected, SMI diagnosis (schizophrenia [ICD-9-CM codes: 295, 297, 298.3, 298.4, 298.9], bipolar disorder [296.00-296.16, 296.40-296.81, 296.89-296.99, 298.1, 648.4], or major depressive disorder [MDD; 296.20-296.36, 296.82, 298.0]), and timing of diagnosis (before or after childbirth, as a proxy of timing of onset). Data analysis was performed on data obtained from April 20, 2017, to May 6, 2020.

Relative to unexposed children, the IRRs of injury hospitalizations for children with two SMI-affected parents, maternal SMI only, and paternal SMI only were 1.85 (95% CI, 1.38-2.48), 1.58 (95% CI, 1.48-1.68), and 1.34 (95% CI, 1.23-1.46), respectively. The IRRs of injury hospitalizations for maternal schizophrenia, bipolar disorder, and MDD were 2.09 (95% CI, 1.82-2.40), 1.77 (95% CI, 1.56-2.00), and 1.38 (95% CI, 1.26-1.50), respectively. The IRRs for paternal schizophrenia, bipolar disorder, and MDD were 1.39 (95% CI, 1.20-1.60), 1.61 (95% CI, 1.39-1.87), and 1.19 (95% CI, 1.05-1.36), respectively. The magnitude of excess risk was similar for children whose parent(s) experienced SMI diagnosed before and after childbirth.

We found children with two SMI-affected parents or at least one parent with schizophrenia or bipolar disorder to be at greatest risk of severe injury requiring hospitalization. These parents may benefit from extra parenting support and injury prevention coaching.