On Thoughts, Threats, and Throwing the Spear

That a malady of the mind, all by itself, might drive a person to violence is an ancient human story. It is at least as old as the Biblical tale of a malign “spirit” that overtook King Saul, filling him with unwarranted fear of his harp-playing protégé, David, and causing him to hurl a javelin to try to pin David to the wall.¹ David was not really out to get Saul, in the scripture’s telling, but that was irrelevant. What mattered was that the “spirit” compelled Saul to think David posed a serious threat—and it was this false belief that enraged the king and animated his attempt to kill his young friend.

In modern times we have rendered a more elaborate story. Our science tells us that the vast majority of those who we now diagnose as mentally ill will never “hurl a spear” in a delusional rage. Most of those who do commit violent acts have no such mental illness to blame, though many would seem to act on the basis of excessive threat perception—an ill-founded fear of harm from others—even in the absence of underlying psychosis. And when a violent act is committed by a person suffering from a disorder of thought, the illness might not sufficiently explain why they did it. Maybe it was because they had a traumatic childhood and are now recapitulating the physically abusive behavior learned from a parent who betrayed their trust. Perhaps they live today in the despair of grinding poverty, have no regular home, and spend their days and nights in a crime-infested neighborhood where quotidian violence marks the rhythm of life. Maybe they are habituated to the excessive use of intoxicating substances that distort perception, disinhibit aggression, destroy relationships, and whose procurement can require associating with criminals.

Interpersonal violence, we have learned, is a complex human behavior caused by a matrix of factors that compound each other and interact to increase or moderate risk. Some causal vectors of violence may be rooted in individual development and personality and learned patterns of action, others in the provocations of an unhealthy social environment, and still others in acute states of drug intoxication. It is against that background that we must understand the unique role of paranoid ideation. We have often presumed that people who would feel threatened enough to lash out in violence against others—others who actually mean them no harm—must have an underlying, persistent psychotic disorder. The authors of this article remind is, with compelling new meta-analytic evidence from 7 UK studies, that such a presumption is mainly wrong. Rather than seeing the nexus of paranoid ideation and violence as a complication of psychotic illness, we should see it as a larger problem, situated among other risk factors, such as antisocial personality disorder, that intersect with psychosis on their edges. Looking to “mental illness” to explain the relationship between excessive threat perception and violence gets it backwards; rather, we should look to paranoid ideation—as an independent problematic thought pattern—to help explain the weak link between psychotic disorders and violence. Paranoid ideation occurs on a spectrum that shades into the normal range of cognitive appraisals of risk and relationships. Interpersonal violence risk, it seems, is distributed along that same continuum.

Mental disorders remain one of leading components of the global burden of disease,² in part due to the indirect consequences of lack of treatment. Improved access to mental health care is desperately needed in communities throughout the world, but barriers persist, in part due to the public’s unwarranted fear that people with psychiatric disorders are likely to be violent. Meanwhile, violent behavior—with its many causes and tentacular social consequences—remains a major cause of injury and mortality. In the United States, lawmakers are proposing mental health system reforms as a solution to a spate of mass shootings by troubled young men. A better and more nuanced scientific understanding of how these 2 public health problems connect—and do not connect—is sorely needed. This careful meta-analytic study of the role that paranoid ideation plays in violent behavior, both apart from and intertwined with psychosis, shines new light on a scientific puzzle that has too long remained obscure. Such an understanding may help frame more targeted and effective approaches both to reduce violence and better integrate people with mental illnesses into community life with the support and acceptance they need.