What is the Relationship between Mental Health Disorders and Violence?

Overview

Dr. Ron Day discusses whether mental health disorders are strongly linked to violence, responding to how often national media connect violent acts to mental illness.

Main Points and Findings

• Public opinion tends to overestimate risk. Surveys show large majorities of the public believe people with mental illness are more dangerous or more likely to be violent (e.g., 46% in a 2013 survey; 35% overall). Beliefs vary by disorder:
  • 32% for major depressive disorder
  • 60% for schizophrenia
• Some advocates and commentators argue there’s “no difference,” but Dr. Day says that position is also inaccurate.

What the Research Literature Indicates

• Overall link is “slight,” not drastic. When mental health disorders are considered as a broad category, the violent risk is only modestly higher than in the general population.
• The elevated risk concentrates in a subset of disorders. Much of the difference comes from disorders such as:
  • Schizophrenia: about 2× the risk of violence compared with the general population; risk rises to about 9× when there is a comorbid substance use disorder.
  • Bipolar disorder: about 3× the risk (again, higher with comorbid substance use).
  • Major depressive disorder: about 3× the risk.
  • Personality disorders: about half of violent crime involves some personality disorder. Antisocial and paranoid personality disorder are especially overrepresented (not all personality disorders are equally implicated).
• Timing matters: for schizophrenia, risk is described as especially elevated during psychotic episodes, rather than being evenly elevated across the whole course of illness.
• Most people with mental illness do not commit violence. Even with increased risk for some groups, the probability of an individual committing violent crime over a lifetime remains low—similar to low base rates in the general population.

Media Responsibility and Nuance

Dr. Day argues that it is irresponsible (and “lazy”) for media to imply mental illness is a major driver of violence to the extent often portrayed. However, he also criticizes the opposite extreme—claims that mental illness does not increase risk at all—calling that inaccurate.

• Best approach: “tell the truth” that certain disorders under certain conditions raise risk, without overstating it.

If Mental Illness Isn’t the Main Cause, What Is?

Violence is framed as complex and multi-causal, not driven by a single factor. Other important risk factors include:

• history of violence
• exposure to violence in childhood
• age
• gender
• stress / being in crisis
• substance use
• low socioeconomic status

Dr. Day concludes that mental health disorders may contribute a small piece of the overall risk when combined with other factors.

Public Health Impact of Misrepresentation

Dr. Day argues that overstating the mental illness–violence link can discourage people from seeking treatment, because they fear being labeled as high risk for violence.

Presenters / Contributors

• Dr. Ron Day