Yes, parental separation or divorce is one of the original adverse childhood experiences (ACEs) identified in the landmark CDC-Kaiser Permanente ACE Study. It falls under the category of “household challenges,” alongside growing up with substance use problems, mental health problems, or an incarcerated household member. About 28.4% of U.S. adults report experiencing parental separation or divorce during childhood, making it the second most commonly reported ACE after emotional abuse.
Where Divorce Fits in the ACE Framework
The original ACE Study identified 10 categories of childhood adversity split into two broad groups: direct child maltreatment (physical, emotional, and sexual abuse, plus physical and emotional neglect) and household challenges that undermine a child’s sense of safety and stability. Parental separation or divorce belongs to the second group. On the standard ACE questionnaire, if your parents separated or divorced before you turned 18, that counts as one point on your ACE score, the same as any other category.
Newer research has proposed expanding the list from 10 to 16 ACEs, adding items like poverty, neighborhood safety, foster care placement, and parental gambling. Even in these expanded models, parental separation or divorce remains a core item. A confirmatory factor analysis published in BMC Pediatrics found that all original ACEs, including divorce, remain relevant and load meaningfully onto the household challenges factor.
Why Divorce Registers as a Childhood Stressor
Divorce isn’t categorized as an ACE because of a moral judgment about family structure. It’s included because of what it does to a child’s biology. Parental separation is considered a toxic stressor, meaning it can trigger strong, prolonged activation of the body’s stress response system. When that system stays activated over weeks or months, it changes how the body responds to stress long-term.
Research shows that early life stress, including parental separation, can disrupt higher-order thinking and emotional processing and negatively alter brain structures and functioning. Children’s stress responses are normally buffered by access to a primary caregiver. When divorce disrupts that access or introduces instability in caregiving, the buffering effect weakens. This is especially pronounced in younger children, whose stress regulation systems are still developing.
Long-Term Health Effects
The ACE framework matters because of a well-documented relationship between childhood adversity and adult health problems. Each ACE category contributes to cumulative risk for conditions including anxiety, depression, obesity, heart disease, lung disease, stroke, and weakened immune function. Divorce adds to that cumulative load the same way other ACEs do.
One large study published in the Sociological Quarterly looked specifically at which ACEs predicted heart attacks in adulthood. Parental divorce remained significantly associated with higher odds of heart attack even after controlling for adult socioeconomic status, mental health, and health behaviors like smoking and exercise. The odds ratio was 1.28, meaning adults who experienced parental divorce as children had roughly 28% higher odds of a heart attack compared to those who didn’t. Notably, healthier adult behaviors didn’t fully explain away this link, suggesting the physiological toll of the stress itself plays a role independent of lifestyle choices.
Not All Divorces Carry the Same Weight
The ACE questionnaire treats divorce as a binary: it either happened or it didn’t. In reality, the impact on children varies enormously depending on how parents handle the separation. Research consistently shows that children tend to improve in well-being when divorce removes them from a high-conflict household, but show declines when it disrupts a low-conflict one. In other words, a child living with parents who fight constantly may actually benefit from a well-managed divorce, while a child who never witnessed obvious conflict may be blindsided by the separation.
What happens after the divorce matters just as much as the divorce itself. Children do best when parents communicate regularly, maintain similar rules across both households, and support each other’s authority. One study comparing different post-divorce parenting styles found that children in cooperative co-parenting arrangements had the fewest behavior problems, scoring about one-fifth of a standard deviation lower than children whose parents operated independently with little communication. Children whose parents barely communicated with each other had the lowest school grades.
The ongoing conflict, instability, and loss of a consistent caregiving relationship are what drive the health effects, not the legal event of divorce itself. A high-conflict marriage that stays intact can be just as damaging, or more so, than a divorce handled with care.
What Buffers the Impact
Having an ACE score that includes divorce doesn’t lock in a particular outcome. The National Scientific Council on the Developing Child has identified four modifiable factors that build resilience against ACEs: a stable relationship with at least one caring adult, strong self-regulation skills, a sense of mastery or competence in some area, and a supportive cultural or faith community. Of these, a supportive relationship with at least one adult is the most protective.
Self-regulation, the ability to manage emotions and impulses, appears to be the strongest predictor of whether a child with four or more ACEs develops a mental health condition. A supportive parent or caregiver relationship is the second strongest. This is encouraging in the context of divorce specifically, because even when one parental relationship is disrupted, maintaining a strong bond with the other parent (or another stable adult like a grandparent or mentor) can meaningfully reduce the risk of long-term harm.
Positive childhood experiences also appear to counterbalance ACEs in a dose-dependent way. Family communication, school connectedness, positive peer relationships, and community support all contribute. Research on teenage girls in the juvenile justice system found that these positive experiences moderated the psychological impact of having four or five ACEs. The takeaway is that ACE scores are not destiny. They describe risk, and that risk can be actively reduced by the quality of relationships and support a child has access to during and after the disruption.
How Divorce Affects Your ACE Score
If you’re calculating your own ACE score or filling out a screening questionnaire, parental separation or divorce counts as one point. The standard adult questionnaire, adapted from the original CDC-Kaiser study, asks whether your parents were ever separated or divorced during your childhood. A “yes” adds one to your total, regardless of the circumstances. Screening tools for children and adolescents, like the PEARLS tool used in California’s pediatric settings, also include parental separation and add a second section covering related adversities like food insecurity and discrimination.
It’s worth remembering that ACE scores are blunt instruments. They tell you how many categories of adversity you experienced, not how severe each one was or how well it was handled. A person with an ACE score of 1 from a bitter, drawn-out custody battle may carry more lasting effects than someone with a score of 3 whose adversities were brief and well-supported. The score is a starting point for understanding risk, not a definitive measure of damage.