In the recently published What Is Mental Illness?, Richard J. McNally unpacks the politically and emotionally fraught debate over how we define mental illness. McNally is the Director of Clinical Training for the Harvard Department of Psychology, and also an advisor to the Diagnostic and Statistical Manual of Mental Disorders, the psychiatric bible that is currently being revised in preparation for the release of its fifth incarnation in 2013. Now that some of the rhetoric surrounding the Arizona shootings has cooled, we asked McNally to interpret what the discourse around that incident signals about public conceptions of mental illness.
Last month’s horrific mass killing in Tucson has awakened concerns about the role of mental illness in violence, especially homicide. Jared Loughner, a 22-year-old college dropout, stands accused of killing six people, including a nine-year-old girl, and wounding 14 others, including Arizona Congresswoman Gabrielle Giffords.
Homicidal rampages inevitably invite speculation about the mental status of perpetrators. Gleaning information from media reports, some eminent psychiatrists conclude that Loughner likely suffers from paranoid schizophrenia. Regardless of the accuracy of these provisional diagnostic conjectures, the facts of the case will surely heighten fears of “psychotic killers” lurking in our midst, poised to explode in murderous rage against citizens in public venues.
In reality, the public image of the dangerousness of people with mental illness is wildly inaccurate. Misconceptions abound regarding madness and mayhem. Claims that people with mental illness are more likely to commit violence than are other people must be qualified by specifying what we mean by the term “mental illness.”
As I outline in my new book, What Is Mental Illness?, the current debate about how we diagnose and treat mental illness is shaped by the Diagnostic and Statistical Manual of Mental Disorders -- the DSM. Indeed, epidemiologic surveys based on the current edition of the DSM show that nearly 50% of American adults have suffered from mental disorder at some point in their lives, and that 25% have been mentally ill during the previous year. However, only about 6% have experienced a severe mental illness, such as schizophrenia or bipolar disorder, within the past year. Few disorders involve a psychotic “break with reality” marked by delusions and hallucinations. Anxiety disorders, nonpsychotic depression, and substance abuse and dependence are far more common than severe mental illness is.
Even when we focus on severe mental illness, especially schizophrenia, we find that concerns about violence, especially homicide, are exaggerated. Consider the landmark MacArthur Violence Risk Assessment Study. The researchers studied 951 patients after their discharge from acute psychiatric facilities, comparing their subsequent commission of violence with a comparison group of 519 residents living in the same neighborhoods as the discharged patients. The MacArthur study refuted many misconceptions about psychosis and violence. Discharged mental patients without symptoms of alcohol or drug abuse were no more likely to commit violence than were their neighbors who had no symptoms of substance abuse. The presence of substance abuse increased the rate of violence in both the patient and comparison groups. Hence, to the extent that a mental disorder increases the odds of violence, it does so by increasing the risk for substance abuse. Patients with a schizophrenia diagnosis were less likely than were patients with other diagnoses to exhibit violence. Most episodes of violence in both groups occurred at home, directed against family members and friends. Strangers were seldom victims. Relative to comparison subjects, patients rarely used weapons.
Ironically, despite widespread public fears of dangerous psychotic patients, individuals suffering from severe mental illness are far more likely to be victims of violence than perpetrators of violence. One study revealed that they experienced violent victimization at four times the rate of the general population. In another study, 25% of those with severe mental illness were victims of violence as compared to only 3% of the general population.
Exposure to violence is especially common among the homeless mentally ill. The largest study of homeless people with severe mental illness indicated that 44% of them had been victims of violence during the previous two months. Although people with these severe conditions are certainly capable of violence, especially if they are abusing drugs and alcohol and suffering from persecutory delusions, they are more likely to be victims than they are victimizers.
To the extent that people with mental illness pose mortal danger to anyone, studies show that they are actually a greater threat to themselves than to other people. According to the Centers for Disease Control, Americans are far more likely to die by suicide than by homicide. This is especially true of people suffering from schizophrenia, bipolar disorder, major depression, and alcoholism. About 10-15% of people with major depression die by their own hands. Between 1 and 2% of all deaths each year in the United States are suicides, and most people who kill themselves have a mental disorder. Nearly three-fourths of them were seriously depressed at the time of their death.
The vast majority of people suffering from schizophrenia and other forms of major mental illness do not commit aggression against other people, let alone mass murder, as Jared Loughner has allegedly done. Even if most people who commit multiple homicides are mentally ill, very few people with mental illness perpetrate such crimes. They are more likely to be victims of violence than perpetrators of violence.
The tragedy in Tucson illustrates the broad social implications of how our clinicians conceptualize mental illness. Indeed, how we distinguish normal mental distress from genuine emotional disorder is a highly contentious issue that lies at the core of the controversy concerning the ongoing revision of the DSM, due to appear in 2013. I wrote What is Mental Illness? to acquaint the general public with the exciting, but often controversial, developments in clinical science that are informing our evolving understanding of what it means to be mentally ill.