By Margarita Nahapetyan
According to American researchers mental illness alone does not predict future violent behavior, but mental illness in combination with substance abuse or dependence does increase the risk of violence.
"Mental illness alone does not increase the risk of violence," explained Eric Elbogen, PhD, an assistant professor in the forensic psychiatry program at the University of North Carolina at Chapel Hill School of Medicine. Mental illness "makes a difference but only in the presence of other risk factors," he said.
Elbogen discovered that younger age and violence history were the top predictors of violent behavior in future, followed by male gender and history of juvenile detention. Other factors included history of physical abuse, recent divorce, unemployment, parental criminal history, severe mental illness with substance abuse, and being a crime victim in the past year.
For the study, the researchers analyzed data collected from nearly 35,000 people. All the participants were asked questions about their mental health, violence history, and use of substances. All of them were part of the National Epidemiological Survey on Alcohol and Related Conditions, conducted by the National Institute on Alcohol Abuse and Alcoholism.
After the first interview which took place between the years of 2001 and 2003, it was clear that 11 per cent of study participants had been diagnosed with mental illness, such as bipolar disorder, major depression, or schizophrenia. Nearly 22 per cent had substance abuse or substance dependence, and more than 9 per cent said they had a severe mental disorder and substance abuse or dependence.
In a second interview conducted between 2004 and 2005, participants were questioned about any violent behavior, such as fighting, attacking or injuring someone, setting fires, or committing a sexual assault, in the time between interviews.
There were more than 3,000 people considered to have severe mental illness - schizophrenia, bipolar disorder and major depression - but no history of either violence or substance abuse. About 50 violent acts were reported between interviews. But when it came to combining mental illness with a history of violence and substance abuse in about 1600 people, the chance of future violence raised 10 times.
When examining participants with schizophrenia, 5.15 per cent reported violent behavior in the time period between the interviews. But when people with the same diagnosis also had substance abuse or dependence problems, 12.66 per cent were found with violent behavior in the time between the interviews.
The researchers also found that those who reported drug or alcohol abuse and also had severe mental illness were 3 times more likely to have been violent, compared with those reporting just mental illness.
The connection between mental illness and violence is there, "but it is not as strong as people think," Elbogen said. "I think a lot of people think mental illness is the usual cause if not the foremost cause of violence," the scientist added bringing an example of survey in which 75 per cent of respondents said they considered people with mental illness as dangerous.
Other experts who reviewed the study said that they hope that the new research will change society's wrong opinion about people with mental diseases. "Having a severe mental illness alone doesn't predict anything," as far as violence is concerned, said Philip Muskin, MD, professor of clinical psychiatry at Columbia University, New York. The new findings, he says, confirm some other studies with similar results.
"You are no more at risk for committing a violent act than anyone in the population," addressed Muskin sufferers with severe mental illnesses, who participated in the study.
Dr. Paul Appelbaum, Columbia University psychiatry professor who was not involved in the study said, "If you take the body of data as a whole, I think what everyone would agree with is, if there is an impact of mental illness on violent behavior it is not very great. And there is no question that the overall contribution of people with serious mental illness to violence in our society as a whole is quite small."
"We are being misled by our own fears," said Appelbaum, "We ought to be concerned about providing good treatment and helping people lead fulfilling lives, not obsessed with protecting ourselves from phantom threats that appear to be unrelated to mental illness."
Mental illness and substance abuse are generally treated separately and United States programs could do a better job treating people with both problems, Appelbaum said.
In other words, the study shows that stereotypes about the mentally ill are often false, and schizophrenia or major depression alone are not likely to turn someone into a criminal.
The study was published in the February issue of the Archives of General Psychiatry.