Recent discussions on gun violence and mass shootings are centered on the topic of mental health. Despite the prevalent belief that mental illness is linked to violence, only about 4 percent of violent incidents in the U.S. are attributed to mental illness. While some mental health disorders — such as schizophrenia, psychosis, substance abuse and bipolar disorder — are associated with a greater risk for aggressive and/or violent behaviors, the majority of people with mental illness are not violent toward others.
Factors such as the availability of guns and interpersonal conflict are much more likely predictors than mental illness for gun violence, according to Jonathan M. Metzl, M.D., Ph.D., and Kenneth T. MacLeish, Ph.D. In addition, large databases tracking gun homicides such as the National Center for Health Statistics indicate that less than 5 percent of gun-related killings are due to mental illness. While the common assumption is that mental illness leads to violence, other circumstances contributing to the violent act — including poor impulse control, neuropsychiatric deficits and underlying personality traits (for example, antisocial personality) — are more important factors. Such circumstances are not solely attributed to mental illness and can affect anyone in the general population.
Severe mental illness and violence
Severe mental illness, such as schizophrenia and other psychoses, are often linked to violence, because of symptoms such as hallucinations (feeling, seeing or hearing sensations that are not actually there) and delusions (false beliefs).
A study examining the risk for anger and subsequent violent behavior in patients with psychosis and specific delusions — of being spied upon, being followed, being plotted against, being under control of person and/or force, insertion of thoughts and having special gifts and/or power — found that none of these delusional beliefs were predictors of subsequent violence. In fact, delusions were only significantly associated with violence when factors such as psychosocial adversity, environmental stressors and comorbid substance abuse were present.
A 2009 literature review indicated that, although people with schizophrenia were four to five times more likely to commit a violent act compared to people in the general population, violence was more prevalent among people who were experiencing a first episode of psychosis or a severe episode resulting in hospitalization. Although people with schizophrenia diagnoses were 20 times more likely to commit homicide, this was mediated by substance abuse among these individuals. Only 1 in 300 people with schizophrenia had actually committed homicide.
People with schizophrenia are more likely to be victims, rather than perpetrators, of violence. Stressful circumstances increase the risk for violent behaviors and aggressive tendencies among people with mental illness. Psychiatric patients tend to act aggressively when they were faced with aversive stimuli such as frustration, activity demand or physical contact. Anger and impulsivity — both of which can predict violence among people in the general population and among those with mental illness — were also predictors of violence.
Substance abuse and violence
Numerous studies show that substance abuse, withdrawal and intoxication are greater contributors to violence than symptoms of mental illness. Data from the MacArthur Community Violence Study (1998) indicated that people with mental illness who did not have a substance abuse diagnosis were involved in significantly less violence than people with a co-occurring substance abuse and mental illness. People with mental illness did not significantly differ from those in the general community in the prevalence of violence. Instead, substance abuse increased the risk for violence among people with mental illness and those in the general community.
The Substance Abuse and Mental Health Services Administration (SAMHSA) further indicated that substantially greater violence erupted when substance abuse and mental illness co-occurred than when either of these disorders existed alone.
Mental illness and suicide
Thomas Insel, M.D., director of the National Institute of Mental Health, contends that people with common mental health disorders — such as anxiety or depression — are more likely to commit suicide than violence toward others or homicide. Even though suicide is the second leading cause of death in the U.S., the majority of suicides do not involve the use of guns. It seems that factors such as the availability of guns and interpersonal conflict are much greater predictors than psychiatric illness for gun-related violence and death.
Mental illness is often blamed for violence, although little evidence links the two. While some symptoms of mental illness can contribute to aggressive and/or violent behavior, numerous people who are diagnosed with mental health disorders are nonviolent.
If you or a loved one is affected by a mental health disorder or you would like more information on the Sovereign Health Group’s mental health, substance abuse or co-occurring disorders treatment programs, please contact our 24/7 helpline.
Written by Amanda Habermann, M.S. clinical psychology, Sovereign Health Group writer