MANCHESTER, England, Aug. 31 (UPI) -- The greatest influence on children's lives, seen or unseen, comes from their parents, including the effects of psychological disorders, according to researchers in England.
A large review of medical data in Denmark reveals a link between violent behavior in children and the psychological disorders their of their parents, suggesting clinicians screen their patients' children for disorders as well.
Researchers at the University of Manchester in England and University of Aarhus in Denmark found children are at higher risk for suicide and violent offenses based on environmental, and possibly genetic, influences, according to the new study, published in the journal JAMA Psychiatry.
"Self-directed and interpersonal violence share some common risk factors such as a parental history of mental illness," researchers wrote in the study. "However, relationships between the full spectrum of parental psychiatric disease and these two related outcomes are unclear."
In a review of 1.74 million people born in Denmark between 1967 and 1997, the researchers found between three and four times the risk for suicide or violent behavior in the children of parents diagnosed with antisocial personality disorder, cannabis misuse and parental suicide attempts. Parental mood disorders, and specifically bipolar disorder, were found to also have a strong influence on the violent behaviors of the children.
The researchers also report the link between parental psychiatric disease and violent behavior were stronger for female children than for males, though the risk for suicide attempts about the same for both sexes.
The researchers note that previous studies have established that suicidal and violent behaviors tend to aggregate within families, pegging it to the intersection of genetics, epigenetics and social and environmental influences. The greater risk for both suicide attempts and overall violent behavior has been linked to parental mental illnesses in the past as well, they report.
In a commentary by researchers at the University of Pittsburgh and Johns Hopkins University, published in JAMA Psychiatry with the new study, convergent risk factors include physiological similarity between parent and child, including brain structure, hormones, impaired executive decision and tendency toward risky decisions.
"To capitalize on these findings, we need further work that can more precisely define the liabilities that are being transmitted, and research to explain individual differences in trajectories of violent and suicidal behavior," Dr. David Brent, Dr. Nadine Melhem and Dr. Holly Wilcox write in the commentary. They add that "given the concerning, decade-long increase in the US suicide rate, we need to put to use what we know now about how to prevent 'common sources of family unhappiness' and thus prevent suicide and violence in the future."