A major new study analysing data from more than 128,000 adults suggests that the elevated risk of depression in adulthood among those who experienced parental divorce in childhood may be largely explained by parental mental illness and substance use, rather than the divorce per se. The work, published in Psychiatry Research, scrutinises whether family structure itself accounts for later distress after taking into account other adverse childhood experiences. The researchers, Mary Kate Schilke of Tyndale University and Esme Fuller-Thomson of the University of Toronto, also examine adults whose parents never married.
The team used data from the 2021-2024 Behavioral Risk Factor Surveillance System, a large US telephone survey. They focused on 128,264 adults and excluded anyone who reported physical or sexual abuse in childhood to avoid confounding trauma.
Before controls, there were clear differences by family structure: lifetime depression rates were 19.2% for adults whose parents were divorced, 18.7% for those with unmarried parents, and 14.1% for those whose parents remained continuously married. For frequent mental distress in the past month, rates were 13.6%, 16.3%, and 8.5% respectively.
When researchers adjusted for adverse childhood experiences, two factors had outsized influence: parental mental illness and parental substance use. Adjusting for parental mental illness reduced the association with depression by 68% for those with divorced parents and 52% for those with unmarried parents; adjusting for parental substance use reduced the link by 49%.
Accounting for all childhood adversities, sociodemographic factors, and adult health behaviours, the link between childhood family structure and adult mental illness ceased to be statistically significant. The authors suggest that a cluster of environmental and genetic factors accompanying a divorce or unmarried household likely drives the higher risk, rather than divorce itself.
Notes on limitations include reliance on self-reported data and the cross-sectional design, which prevents establishing a timeline of events. The researchers cannot determine whether a parent’s mental illness began before or after a divorce, or how old the child was at the time of separation. The category of unmarried parents is also broad, combining single parents and those who lived together without marriage, which represent different family environments. Additionally, childhood socioeconomic status was not tracked in the data.
The study is titled “Long After the Split: The Association Between Parental Divorce and Mental Health in Adults” and is authored by Mary Kate Schilke, Philip Baiden, and Esme Fuller-Thomson.
