Mentally Ill & Potential Violence

Calls related to severely mentally ill individuals are some of the most troublesome and potentially violent calls officers respond to. People with mental illnesses commit police homicides at a rate 5.5 times greater than the general population.


In September, 2008, 28 year old Isaac Zamora shot and killed a sheriff's deputy and five other people during a shooting rampage near his rural home and a high-speed chase along Interstate 5 in Alger, WA. He wounded two others. Over the past decade, he demonstrated increasing signs of serious mental illness, ranging from suicide attempts to auditory hallucinations. He was not taking his prescribed medication at the time of the homicides. Zamora had been diagnosed over the years with both bipolar disorder and schizophrenia.

Calls related to mentally ill subjects are some of the most troublesome and potentially violent calls officers respond to. In fact, 9% of all dispatch radio calls are related to mental illness. Tragic encounters between the mentally ill and law enforcement officers happen regularly, especially with schizophrenic and/or bipolar subjects not following a medication regime. People with mental illnesses commit police homicides at a rate 5.5 times greater than the general population.

Severe Mental Illness and Violence Facts

These statistics are from studies by the Treatment Advocacy Center

  • Approximately 1,500 homicides a year in the US are committed by individuals with severe psychiatric disorders.
  • There are approximately 4.5 million Americans with severe mental illness. Approximately 2.3 million are bipolar, and 2.2 million have schizophrenia. Of these individuals approximately 1.8 million are not be treated for their illnesses.
  • Law enforcement officers are more likely to be killed by a person with mental illness than by other assailants, including those who had a prior arrest for assaulting police or resisting arrest.
  • 13% of in the line of duty officer deaths are related to mental illness.
  • A Department of Justice report found that: 12.3 % of defendants who kill their spouse, 15.8%, who kill their own child, 25.1% who kill their parents and 17.3% of siblings who kill a sibling have all had a history of untreated mental illness.
  • The risk of committing a homicide is about 10 times greater for schizophrenics of both genders than for the general population.
  • The risk is more than 17 times greater for men with schizophrenia and coexisting alcoholism.
  • One-third of the people killed by police showed signs of being emotionally disturbed or mentally ill at the time of the incident.
  • People with severe mental illnesses who ARE taking medication are no more likely to be dangerous than the general population.
  • People with mental illnesses are four times more likely than the general public to be killed by police in justifiable homicides.
  • People with mental illness are 3-4 times more likely to be victims of violent crime than the rest of the population.
  • Suicide is the number one cause of premature death among people with schizophrenia; an estimated 10%-13% kill themselves. Suicide is even more pervasive in individuals with bipolar disorder; an estimated 15%-17% percent will take their own lives.

Predicting Violence in Severely Mentally Ill Individuals

The three strongest predictors of violence for any subject a law enforcer encounters are:

  1. a history of past violence
  2. drug and alcohol abuse
  3. a serious mental illness that is not being treated with medication.

The mentally ill subject most likely to become violent suffers from paranoid delusions, auditory hallucinations or both. A paranoid schizophrenic believes that others are out to harm him and a feeling that their mind is being controlled by outside forces or thoughts that are being placed in his/her head. At a crowded event a man may turn around and strike a child, believing he was just hit by laser beams which will render him sterile. Auditory hallucinations are a hallmark of psychosis. Command hallucinations, in which voices tell a psychotic individual what to do, is one of the most compelling predictors of violence.

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