About 3,000 times a year, someone in the US kills their child. It’s a tragic phenomenon no one has tried to understand— until now.
Timothy Mariano, MD, PhD RES’15 and Wade Myers, MD, professor of psychiatry and human behavior and a forensic psychiatrist at Rhode Island Hospital, published a study in the March issue of Forensic Science International that offers the first statistical analysis of filicide, drawing on 32 years of data on more than 94,000 arrests.
Their research could help identify patterns among filicide cases, which could in turn aid in studying its causes. “To know more about the epidemiology of this crime will hopefully help medical practitioners to identify people who are at risk for committing such crimes,” Mariano, the lead author, says, “and that will help us with prevention, which is the ultimate goal of this research.”
Understanding filicide can help challenge myths and stereotypes about the crime, Myers adds. For example, the data, mined from the FBI’s Supplementary Homicide Reports, show that men and women are almost equally likely to kill infants, though men were more likely to kill older children. Stepchildren are at no greater risk than biological children, and adult children account for nearly one in five filicide victims, suggesting it’s a lifetime risk.
Perhaps the only silver lining in the research—if one can be said to exist at all—is that filicides appear to be on the decline. The total number of cases has drifted slightly downward since the 1990s, even as the population has grown.
Mariano, Myers, and co-author Heng Choon Chan, PhD, of the City University of Hong Kong, found that more than 58 percent of victims in the study were male. A father killing a son was the most likely filicide scenario, representing nearly a quarter of such deaths; women killing a stepchild accounted for less than 1 percent of cases.
The most common method of killing, especially of infants, was with “personal weapons,” such as beating, choking, or drowning. As victims aged, firearms were more common, and men were much more likely than women to use them.
The paper suggests three main hypotheses about the motives for filicide. One is that at least some offenders have mental illness that derives from low levels of the neurotransmitter serotonin. Not only is that borne out in some animal studies, but the most typical ages of parents in the data—18 to 30 years—are when many serotonin-related illnesses occur, like depression and schizophrenia.
Because men committed more than 57 percent of the killings, the researchers also considered high levels of testosterone, which appear to coincide with higher rates of filicide in animal studies.
The final theory pertains to “the unwanted child.” This evolutionarily motivated idea, also informed by other studies, suggests that parents, particularly young mothers, may kill young children who are sick or for whom they feel they cannot provide care.
Neither the data nor the hypotheses definitively explain filicide, but they can help researchers focus their inquiries. “Hopefully future research will continue to improve society’s ability to identify, manage, and treat populations at risk,” the authors write.