Violence and Mental Illness—What Does the Science Say?

Are people who have a serious mental illness naturally more violent than other people? NO.

Many people with serious mental illnesses experience the active symptoms of their illness (e.g., hallucinations, delusional thinking, impaired judgment) episodically, or in a cyclical, on-and-off way.

When a person with a serious mental illness is managing that illness with psychotropic medication and healthy lifestyle—good diet, good sleep hygiene, good physical healthcare, reduced life stress, meaningful daily activity, social support, and sobriety—most of the active symptoms of mental illness fade away.

Of course there’s a catch. Many people who have a serious mental illness have serious barriers to getting proper treatment and managing a healthy recovery lifestyle.

After a violent event involving someone with a mental illness, we often hear family members telling the news media, “We tried to get him help, but couldn’t find it.”

The research does indicate that people who are experiencing symptoms of untreated mental illness, especially if they are also under the influence of alcohol or other drugs, are somewhat more likely to act violently. And the research says that people with schizophrenia who are receiving proper treatment are no more violent than people without schizophrenia.

Despite lurid news stories, the “violent behavior” of people with untreated mental illness more often takes the form of self-harm or suicide than assaults or homicide.

The truth that we know from scientific research is that people with mental illness do not contribute significantly to the overall incidence of violent crime in America…and people with mental illness are 11 times more likely than others to be the victim of a violent crime.  

Thomas Insel, MD, Director of NIMH

Thomas R. Insel, MD

After the shootings of U.S. Representative Gabrielle Giffords and 18 other people at a grocery store in Tucson, Thomas R. Insel, M.D., the Director of the National Institute of Mental Health, wrote this :

“When a tragedy occurs like the shooting in Tucson, all of us seek an explanation. While there remain many questions, a leading hypothesis is that the suspect…has a serious mental illness (SMI), such as schizophrenia.

The topic of violence and mental illness is never an easy discussion: with issues such as stigma, incarceration, public safety, and involuntary treatment in the mix.

There is a legitimate concern that talking about violence and mental illness in the same sentence increases the likelihood that people with serious illness will be further marginalized and less likely to receive appropriate care…

Is violence more common in people with SMI? Yes, during an episode of psychosis, especially psychosis associated with paranoia and so-called “command hallucinations,” the risk of violence is increased.

People with [these active symptoms of untreated] severe mental illness are up to three times more likely to be violent; when associated with substance abuse disorders, the risk may increase much further. 1

But, mental illness contributes very little to the overall rate of violence in the community. Most people with SMI are not violent, and most violent acts are not committed by people with SMI.

In fact, people with SMI are actually at higher risk of being victims of violence than perpetrators. Teplin et al found that those with sever mental illness are 11 times more likely to be victims of violent crime than the general population. 2

The most common form of violence associated with mental illness is not against others, but rather, against oneself.

In 2007, the most recent year for which we have statistics, there were almost 35,000 suicides, nearly twice the rate of homicides. Suicide is the 10th leading cause of death in the United States.3 Although it is not possible to know what prompted every suicide, it is safe to say that unrecognized, untreated mental illness is a leading culprit.

Treatment may be the key to reducing the risk of violence, whether that violence is self-directed or directed at others. Research has suggested that those with schizophrenia whose psychotic symptoms are controlled are no more violent than those without severe mental illness.4 It’s likely that treatment not only helps ease the symptoms of mental illness, but also curbs the potential for violence as well.

…We should be working harder to ensure people with SMI receive the care they need. Early intervention offers the best hope to prevent more tragedies in the future.”

1  Swanson JW. Mental disorder, substance abuse, and community violence: an epidemiological approach. In: Monahan J, Steadman HJ, eds. Violence and mental disorder: developments in risk assessment. Chicago: University of Chicago Press, 1994:101-36.

2  Teplin et al. Crime victimization in adults with severe mental illness. Archives of General Psychiatry, 62. 911-921. 2005 Aug.

3  Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. Web-based Injury Statistics Query and Reporting System (WISQARS).

4  Steadman HJ, Mulvey EP, Monahan J, et al. Violence by people discharged from acute psychiatric inpatient facilities and by others in the same neighborhoods. Archives of General Psychiatry, 55. 393-401. 1998