Violence and Mental Illness

People who have mental illnesses very rarely make the news. The overwhelming majority even those with severe disorders such as schizophrenia, bipolar disorder, panic disorder, depression, and obsessive compulsive disorderwant only to live in dignity, free from the suffering brought by their illnesses. Yet, according to a 1993 survey commissioned by Parade Magazineover 57 percent of Americans think mentally ill people are more likely to commit acts of violence than other people.

People often fear what they do not understand, and for many of us, mental illnesses fall into that category. This fear is amplified by movies with names like "Psycho!" or splashy news accounts of serial killer trials where the word "insane" (a legal term, not a psychiatric diagnosis) is heard often. The fear also stems from the common misconception that the term "mental illness" is a diagnosis, and that all mental illnesses thus have similar symptoms, making all people who suffer with them equally suspect and dangerous.

Recent research has shown, that the vast majority of people who are violent do not suffer from mental illnesses. However, there is a certain small subgroup of people with severe and persistent mental illnesses who are at risk of becoming violent, with violence defined as threatening, hitting, fighting or otherwise hurting another person.

How Mental Illnesses Affect People

The APA Statement on Prediction of Dangerousness, says that "psychiatrists have no special knowledge or ability with which to predict dangerous behavior. Studies have shown that even with patients in which there is a history of violent acts, predictions of future violence will be wrong for two out of every three patients." There are just too many variables in the biopsychosocial nature of mental illnesses.

Mental illnesses are biological, arising in part from disturbances in brain or other bodysystem chemistry; they are psychological, manifesting in disturbances in thought and/or emotion; and they are social, arising in part from patients' social and cultural environmenthow they are raised, the norms of their community, what sorts of stress they face in their everyday lives. Psychiatrists always take into account these three intertwined areas of an ill person's life in diagnosis and in designing an effective treatment plan. However, they are not always helpful in predicting behavior.

Some Types of Mental Illnesses Increase the Risk of Violent Behavior

Recent research (1, 2, 3, 4) suggests that people with neurological impairments and psychoses are at greater risk of becoming violent. Neurological impairmentsusually stemming from diseases such as Huntington's chorea or from head injuries which damage the braincan have psychological effects, interfering with a person's ability to interpret what is real, and to act or relate to others appropriately. Psychosis, according to the American Psychiatric Glossary, (American Psychiatric Press, Inc., 1994) is "a severe mental disorder characterized by gross impairment in reality testing, typically shown by delusions, hallucinations, disorganized speech, or disorganized or catatonic behavior." Most often, psychosis stems from schizophrenia, but it can also be a symptom in other delusional disorders and some mood disorders, and can arise from abnormalities in brain structure.

The government's 1983 Epidemiologic Catchment Area survey of people with mental illnesses reported that people with schizophrenia (which affects perhaps one in every 100 people) were nearly nine times more likely thanthose among the general population to have fought with others or to have hit their partner in the past year, eight times more likely to have hit their child, and nearly 22 times more likely to have used a weapon (5).

Not all people with psychosis or brain injuries become violent, nor will they become violent under all circumstances. A person who is ill with schizophrenia, for instance, is not psychotic all the time. Also, not all people with schizophrenia have delusional beliefs that others are persecuting or controlling them, and it is this delusional belief that can often lead to a violent outburst (6). The symptoms of the illness may wax and wane, and may vary in intensity. Medication and a supportive, nonstressful environment can often largely control these symptoms. People with neurological impairments are more likely to be habitually violent (3).

Conditions That Increase the Risk of Violence

The conditions likely to increase the risk of violence are the same, whether a person has a mental illness or not. Studies of violence and mental illness have shown that people with mental illness who come from violent backgrounds are often violent themselvesa finding that echoes the incidence among the general population (7). One survey (8) held that "chaotic, violent family environments in which alcohol or substance use is common, ongoing conflict among family members, and a controlling atmosphere [are] associated with violence by persons with mental illness." This survey also found that "this tradition is also predictive of violence in the general population."

The increased risk that a person will become violent is most associated with the social part of the "biopsychosocial" equation. According to recent studies, a person with psychosis or a neurological impairment, in an unpredictable, stressful environment with little family and community support and little personal understanding of his or her illness, may be at increased risk for violent behavior.

Such conditions are all too common in our societyespecially in our cities: family and social violence are common, as is substance abuse. Stress can aggravate the symptoms of most mental illnesses, and unfortunately, stress is often an unavoidable part of a mentally ill person's life. An illness which causes hallucinations, delusions, bizarre ideas and behavior can severely limit a person's opportunities in relationships and at work. Very often people with severe mental illness end up living in reduced circumstances, forced to do lowpaying work when they can work at all, living in dangerous neighborhoods or, much too often, homeless. Such an environment aggravates the symptoms of a person struggling with psychosis (the threatening environment worsening the fears, for instance, of a person with paranoid delusions).

If the person is under treatment, stressful conditions, combined with the unpleasant side effects of some antipsychotic medications, may cause him or her to take medications irregularly or to stop taking them entirely. The patient may begin abusing street drugs in an effort to more actively numb the pain of the illnesswhich almost inevitably has the opposite effect, worsening the symptoms and counteracting the effects of prescribed medications.

Because the illness has already eroded the person's ability to perceive reality, this combination of conditions can increase the risk of violence. In one survey of people with mental illness for instance (8), respondents who became violent first felt threatened and attacked by the people they attacked. They did not perceive themselves to be more threatening or hostile to others than other mentally ill individuals polled by the survey who did not behave violently.

The Risk to Others

Studies have shown that family members are most at risk of a violent act committed by a mentally ill person. People with severe mental illnesses are often dependent on family for care. Within the family, the person most involved in the ill person's careusually the motheris most at risk, with the violent person usually being a son or a spouse. One study of patients admitted to psychiatric hospitals found that, among thse who had attacked people during the time close to their admission, 65 percent of the sample had attacked a family member (9). Strangers or people outside the ill person's social network are much more rarely targets of violence.

Societal Violence and Mental Illnesses

Research has shown no clearcut relationship between societal violence and the development of specific mental disorders. In recent times, the violence on our urban streets has been a matter of intense public concern, however, researchers cannot demonstrate a clear cause and effect relationship between such violence and the development of specific mental illnesses. We do know that violence suffered in childhood in the forms of sexual or physical abuse or neglecthas longterm consequences, leading to behavioral problems in later life and cycles of familial violence passed on from generation to generation. While the violence in our society doesn't necessarily produce mental illnesses, it is clear that it can certainly worsen their symptoms.

Research also shows that a supportive, understanding unrestrictive environment, while it cannot completely assuage all their symptoms, can at least help people with severe mental illness as they try to avoid relapse. As long as people maintain their medication, studies have shown that those with serious mental illnesses are no more dangerous than the general population. Also, people who are receiving regular psychotherapeutic support from a mental health professional are much less likely to commit a violent act (10).

Although research has shown that providing consistent medical treatment with medication, coupled with comprehensive social support services, is the best way to prevent violent behavior among the small minority of mentally ill people who are at risk. More research is needed to gain an understanding of the increased risk of violence among a small number of mentally ill people, and to suggest additional solutions. Meanwhile there is much that can be done in our communities now. Local service and advocacy organizations are working to support the continuation and expansion of communitybased public mental health services, which are critical to providing continuing care to people with sever and chronic mental illnesses. Treatments and support services exist, today, for people with mental illnesses, including treatments for that minority that do exhibit assaultive behaviorand these treatments work. But because of continued discrimination in health insurance coverage of mental illnesses and chronic underfunding of public mental health programs, they are not accessible to all who need them.


(1) Volkow ND, Tancredi L: "Neural Substrates of Violent Behavior: A Preliminary Study with Positron Emission Tomography," British Journal of Psychiatry 151:668673, 1987

(2) Tardiff K, Sweillam A: Assault, Suicide and Mental Illness," Archives of General Psychiatry, 37:164169, 1980)

(3) Krakowski M, Czobor P: "Clinical Symptoms, Neurological Impairment, and Predication of Violence in Psychiatric Patients," Hospital and Community Psychiatry 45:7, 1994

(4) Krakowski M, Convit A, Jaeger J, et al: "Neurological Impairment in Violent Schizophrenic Inpatients," American Journal of Psychiatry 146:849853, 1989

(5)Swanson JW, Holzer CE, Ganju VK, et al: "Violence and Psychiatric Disorder in the Community: Evidence from the Epidemiologic Catchment Area Surveys," Hospital and Community Psychiatry 41:761770, 1990

(6) Mulvey, E: "Assessing the Evidence of A Link between Mental Illness and Violence," Hospital and Community Psychiatry 45:7, 1994

(7) Gelles R: "Violence in the Family: A Review of the Research," in Family Violence, Second Edition, London: Sage, 1987

(8) Estroff S, Zimmer C, Lachiocotte W, Benoit J: "The Influence of Social Networks and Social Support on Violence by Persons with Serious Mental Illness," Hospital and Community Psychiatry 45:7, 1994

(9) Tardiff K: "Characteristics of Assaultive Patients in Private Hospitals," American Journal of Psychiatry 141:12321235, 1984

(10) Torrey EF: "Violent Behavior by Individuals with Serious Mental Illness," Hospital and Community Psychiatry 45:7, 1994

Resources for further reading

American Psychiatric Association: Statement on Prediction of Dangerousness, March 18, 1983.

American Psychiatric Association Hospital and Community Psychiatry Service: Management of Violent Behavior: Collected Articles from Hospital and Community Psychiatry, Washington, DC: APA, 1990

Bednar R (et al): Psychotherapy with Highrisk Clients: Legal and Professional Standards, Pacific Grove, CA: Cole Publishing, 1991

Felthous A: The Psychotherapist's Duty to Warn or Protect, Springfield, IL: Thomas, 1989

National Mental Health Association, Aiding People in Conflict: A Manual for Law Enforcement, Alexandria, VA: NMHA, 1988

Pernanen K: Alcohol in Human Violence, New York: Guilford, 1991

Toch H: Violent Men: An Inquiry into the Psychology of Violence, Washington, DC: American Psychological Association, 1992