Researchers from Northwestern University suggest that many mental disorders do not appear to predict future violent behavior, with the exception of substance use disorders. Dubbed the Northwestern Juvenile Project, the longitudinal study assessed violence and psychiatric disorders via self-report in more than 1,600 inmates aged 13 to 25 at the Cook County Juvenile Temporary Detention Center in Chicago, IL.
For the study, published in the April 2015 issue of the Journal of the American Academy of Child & Adolescent Psychiatry, participants (56% African American, 28% Hispanic, 36% female) were interviewed as many as four times between 3 and 5 years after detention in 1995 to 1998. The study team used generalized estimating equations and logistic regression were used to examine contemporaneous relationships were examined between psychiatric disorders and violence as youth age and whether the presence of a psychiatric disorder predicts subsequent violence.
Between 3 and 5 years after detention, rates of any violence decreased overall, from 35% to 21% among males and from 20% to 17% among females. Only females with a marijuana use disorder and males with other drug use disorders 3 years after detention had greater odds of any violence 2 years later, when compared with those with no mental disorders.
“Our findings are relevant to the recent tragic plane crash in the French Alps,” said co-author Linda Teplin, Owen L. Coon Professor of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine. “Our findings show that no one could have predicted that the pilot—who apparently suffered from depression—would perpetrate this violent act. It is not merely a suicide, but an act of mass homicide.”
The investigators did find a contemporaneous relationship between all specific mental disorders assessed in the study and violence, except for major depressive disorder/dysthymia among males. Compared with those who had not mental disorder, males and females with any mental disorder had greater odds of any violence (adjusted odds ratio, 3.0 for males, 4.4 for females). Males with mania were more than twice as likely to report current violence as those without mania.
The researchers caution, however, that these relationships may not necessarily be causal. Detained youth with psychiatric disorders tend to have competing factors in their lives that could lead to violence, worsen psychiatric disorders, or both. For example, residing in violent and impoverished neighborhoods could increase one’s risk for violent behavior and worsen their mental disorder.
“Providing comprehensive treatment to persons with some psychiatric disorders could reduce violence,” said lead authors Katherine Elkington, PhD, assistant professor of clinical psychology and psychiatry, Columbia University Medical School and New York Psychiatric Institute. “We must improve how we address multiple problems—including violent behavior—as part of psychiatric treatment.”