Physically Assaulted Kids See Double the Risk of Mental Illness

— Diagnosis of a new mental health disorder greatest in the year after assault

by
Shannon Firth, Washington Correspondent, MedPage Today
August 16, 2023

Children exposed to physical assault were at higher risk of a mental illness diagnosis over subsequent years, with the greatest risk seen in the year after the assault, a large population-based study from Ontario, Canada found.

In the age-matched cohort study, children seen for physical assault in an acute care setting were nearly twice as likely to be diagnosed with a mental illness over a median follow-up of nearly 7 years when compared with children who were not assaulted (adjusted HR 1.96, 95% CI 1.85-2.08), reported Natasha Ruth Saunders, MD, MSc, of the Hospital for Sick Children in Toronto, and colleagues.

“Although it was expected that children who experienced assault would have a higher risk of mental illness, a novel finding from our study is that the risk was highest in the first year following physical assault,” the researchers wrote in JAMA Network Open.

In that initial year after the assault, the risk for a new mental health diagnosis was approximately three times higher compared with unexposed kids (adjusted HR 3.08, 95% CI 2.68-3.54), and the elevated risk continued over the following 3 years (adjusted HR 2.01, 95% CI 1.84-2.19) and at 4 years and beyond (adjusted HR 1.53, 95% CI 1.39-1.69).

“These findings highlight that there may be a critical opportunity to support children, and potentially their mothers, in the period immediately following their assault,” Saunders and co-authors suggested, also alluding to the finding that the mothers of physically assaulted kids had higher rates of active mental illness or a history of their own physical or sexual assaults.

Researchers found that children in the study who were physically assaulted were more likely to receive their initial mental illness diagnosis in an acute care setting than children who were not physically assaulted (14% vs 2.8%).

These “findings could mean that childhood survivors of physical assault have a more severe presentation of mental illness or present more often in the context of a mental health crisis,” according to the study authors. “It is also possible that those experiencing assault seek care more frequently in an acute care setting because of the difficult access to timely outpatient mental health care in this more vulnerable population of children and youths.”

The study from Saunders and colleagues used multiple databases and included 5,487 children ages 0 to 13 years who from 2006 to 2014 presented to an emergency department (ED) or were hospitalized for an acute physical assault in Ontario. They were matched in a 1:4 ratio by age and maternal linkage to 21,948 children who had not been assaulted during that time. Both groups were tracked for at least 5 years (until their 18th birthday or study end in March 2019).

An incident diagnosis of mental illness or completed suicide was the primary outcome.

During the nearly 7 years of follow-up, 39% of the children who had been physically assaulted had a mental health diagnosis as compared with 23% of those who had not been assaulted. Non-psychotic disorders, such as mood and anxiety disorders, were the most common diagnosis (16.2% vs 10.6%, respectively); followed by select childhood behavior disorders, such as attention-deficit/hyperactivity disorder and oppositional defiant disorder or conduct disorder (9.9% vs 5.2%); and substance use disorders (2.4% vs 0.4%).

Significant links were observed between assault and most diagnostic categories, the researchers found, with the greatest associations seen for substance use disorder in the first year following an assault (crude HR, 17.33, 95% CI 7.14-42.11) and intentional self-injury in the initial 4 years (adjusted HR 8.50, 95% CI 4.45-16.21).

Children had an average age of 7 years at the index event or start of follow-up. The group exposed to physical assault had a higher proportion of boys (55% vs 45%) and non-immigrants (95% vs 91%), and were more likely to have mothers with active mental illness (35% vs 19%), be in the highest quintile of the material deprivation index (33% vs 24%), or live in rural areas (22% vs 6%).

Among other reasons, kids were excluded from the study if they died during their initial acute care visit for physical assault, if intentional self-injury was also diagnosed on that visit, or if they had a prior history of mental illness — this last criterion resulted in close to half of all children with a diagnosis of physical assault in the acute care setting being excluded.

Limitations include that children who are abused or assaulted often are not hospitalized or do not visit an ED, so the number of children exposed to assault in the study is likely an underestimate.

Other issues included unmeasured confounders; that perpetrator characteristics were not assessed but could influence which children get care; and that a health system encounter for an injury could result in a higher chance of mental illness detection, though Saunders’ group noted that the latter was “partially mitigated by using a washout period for mental illness identification following the index injury.”