Mass Shooters and the Psychopathology Spectrum


When it comes to mass shooters, persistent emotional disturbance is not the same as frank “mental illness.” Exploring the spectrum of psychopathology.

Important elements of mental disorders

Figure. Important elements of mental disorders

With Commentary by James L. Knoll, IV, MD, and J. Reid Meloy, PhD: The Mass Shooter and His Mental Functioning.

To read letter(s) to the editor and responses from the author regarding this post, click here. To submit your comment, please send it to for consideration.

Core article concept: schizophrenia


Are most individuals who carry out mass shootings “mentally ill”? Many in the general public-and some mental health professionals-continue to claim they are.1 This claim persists, despite findings to the contrary by forensic psychiatrists and several official investigations.2

It is clear that the disagreement has both empirical and conceptual components. On the one hand, we have empirical research looking at the prevalence of “serious mental illness” among those who have carried out mass shootings (usually defined as involving four or more victims). In general, the best available research finds very little clinical evidence that most mass shooters have suffered from serious mental illness-usually taken to mean schizophrenia and related psychotic disorders; bipolar disorder; or major depressive disorder.3 On the other hand, many in the general public and the media seem to view the concept of “mental illness” much more broadly than do most forensic psychiatrists or experts in violence assessment. The question often put to psychiatrists by those in the media is, “How can someone who randomly shoots ten or twenty people not be mentally ill? If that’s not mental illness, what is it?”4

The disagreement is not reducible to a naive “mistake” on the part of the media or the general public. That is, a satisfactory response to the question posed above cannot be a dismissive, “You simply don’t understand what mental illness is!” The problem is much more complex. It calls upon us to invoke Plato, whose reference (in the Phaedrus 265e) to “carving Nature at its joints” has fueled scientific controversies for 2500 years. What Plato was conveying in his “carving” metaphor is summarized by Matthew H. Slater and Andrea Borghini; specifically, Plato believed in “. . . the objective, independent reality of many different natural kinds of things. The members of such kinds would be the meat between the joints along which good theories cut.”5

Our modern-day debate regarding the “nature” of mental illness is a direct outgrowth of Platonic philosophy. As philosopher Kelso Cratsley6 has put it,

Much of the current debate hinges on whether mental disorder should be understood as relatively discrete categories of illness or as dimensional gradations of symptoms that cut across traditional taxonomic boundaries.”6

In contrast to the notion of “natural kinds” or distinct categories in the realm of psychiatric disorders, there is “…growing evidence point[ing] to the superiority of a dimensional approach to the science of mental illness.”7 For example, it is possible to aggregate psychiatric symptoms into three domains along a dimension of psychopathology: 1) externalizing, 2) internalizing, and 3) psychotic experience.8 My colleagues James L. Knoll IV, MD, and J. Reid Meloy, PhD, explicate this model in the companion piece that follows this article.

In my view, the Platonic concept of discrete categories or “natural kinds” is not well-suited to psychiatric illness or, indeed, to most phenomena in the realm of clinical medicine. As Dr Kenneth F. Schaffner9notes,

The notion that the entities that are fundamental in a scientific area need to be discrete and separable is an idea that works well in some sciences such as physics and chemistry. But these types of entities are rarely found in biology . . .9

In this essay, I argue against a discrete, binary notion of “mental illness” or “mental disorder”-(ie. as a category completely distinct from “mental health”). Instead, I develop the concept of a continuum of mental, behavioral and emotional disturbance. Despite its categorical approach, the DSM-5 is by no means hostile to this view; stating, for example, that “The boundaries between normality and pathology vary across cultures for specific types of behaviors . . . hence, the level at which an experience becomes problematic or pathological will differ.”10(p.14)

With the aim of providing a heuristic model, I examine three broad divisions along the continuum of pathology, with one subtly grading into the other: transient, stress-related emotional turmoil; persistent emotional disturbance (PED); and mental illness/disorder. I then apply these broad divisions to the status of the “mass shooter.” I argue, in effect, that most mass shooters fall roughly (but not invariably) in the middle of this continuum, ie, somewhere between “transient, stress-related emotional turmoil” (on the far left); and “mental illness/disorder” (on the far right). I call this middle ground of psychopathology, “Persistent emotional disturbance.” And, while PED cannot be considered an instantiation of “mental health,” neither does it conform to psychiatry’s construct of “mental illness”-at least, not to our usual understanding of “serious mental illness.” The diagram below shows how-as we move from left to right-the “disease-like properties” of the condition gradually increase.

I now elaborate on these three major divisions, with the caveat that these are not “categories” in the Platonic sense, or in the sense employed in DSM-5; rather, they represent progressive but subtle gradations of psychopathology.

Transient, stress-related emotional turmoil

Transient, stress-related emotional turmoil (TSRET) is familiar to nearly everyone and might even be considered emblematic of “the human condition.” It generally occurs in the context of major life events (both positive and negative); interpersonal conflict; or significant loss. Although emotional reactions in these contexts can be intense, they are not inherently pathological and rarely cause significant or prolonged dysfunction. For example, following bereavement (the death of a loved one), it is “normal” to experience a range of strong and sometimes conflicting emotions. These may fluctuate from “shock, anguish, loss, anger, guilt, regret” to more positive emotions, such as “relief, joy, peace, and happiness that emerge after the loss of an important person.”11 “Uncomplicated bereavement” (included in the “V” code section of DSM-5) differs in important respects from pathological states, such as “complicated grief” and major depressive disorder.11

TSRET may also be related to the person’s developmental stage, as we see in many psychologically “normal” adolescents and teens. Thus, as McLaughlin and colleagues12 note, the adolescent years are typically characterized by frequent and intense emotions; elevations in emotional and physiological reactivity; and greater emotional lability than are typical in either childhood or adulthood.

Moreover, “Compared with children and adults, adolescents also experience more intense emotions in both positive and negative domains.”12 Impulsive and sometimes risky behaviors are a common accompaniment of adolescent emotional turmoil. Although these emotional and behavioral features are not inherently pathological, adolescence is nevertheless a period of increased risk for psychopathology.12

Persistent emotional disturbance

In this portion of the continuum, we find individuals with more chronic and severe emotional problems, though still falling short of clinically significant mental illness. However, in some instances, the line between characterologically-based PED and full-fledged DSM-5 personality disorder becomes exceedingly fine, and this may indeed be the case with a subgroup of mass shooters. By way of describing the psychological profile of the prototypical mass shooter, consider the following composite case.


“Tyler” is a 19-year-old, single, unemployed high school dropout. Middle-school and high school records show that Tyler was often the target of bullying by older boys, who often teased Tyler about his slight build and high-pitched voice. He was working as a short-order cook and doing various “odd jobs,” but was recently fired, after getting into a heated argument with his boss. For most of his life, Tyler has felt like “the odd man out” and that he’s always gotten “the short end of the stick.” He posts angry rants regularly on social media, arguing that “the whole damn system is stacked against me,” and complaining that “it’s always the minorities that get all the goodies, even though they shouldn’t even be in this country!”

Tyler has long held a grudge against the high school he attended, accusing the administration of “targeting me for oppression and exploitation” and fantasizing about “a revolution born in blood to overthrow the elites.” On social media, Tyler recently wrote, “I’m the only true-born leader who can purify this world of its filthy elements.” He has made a careful study of mass shootings in the U.S. and expresses admiration for the shooters, writing, “These are the true soldiers of the revolution.” For several years, Tyler has been obsessed with firearms and ammunition, and has recently entertained fantasies of “shooting up” his former place of employment.


I suspect most readers-quite understandably-will find Tyler’s feelings and beliefs frightening and disturbing. Yet there is a good chance that, examined clinically, Tyler would not be diagnosed with a DSM-5 mental illness. To be sure: Tyler is hardly a model of mental health. He is what many psychiatrists would call “emotionally disturbed” but not clearly “mentally ill.” His worldview is one of anger, resentment, victimization, and narcissistic grandiosity.

But Tyler is likely not psychotic or suffering from what psychiatrists would consider “serious mental illness,” such as schizophrenia, bipolar disorder, or major depression. Though Tyler may have some features of one or more personality disorders (eg, paranoid or narcissistic personality disorder), he probably falls short of DSM-5’s Criterion C for general personality disorder (ie, “. . . clinically significant distress or impairment in social, occupational, or other important areas of functioning”).10(p645)

The critical term here is clinically significant, which clearly requires careful judgment on the part of the psychiatrist, and on which point reasonable clinicians may disagree. On balance, I would place individuals with Tyler’s profile somewhere in the middle of the proposed continuum-perhaps somewhat “right of center.”

Mental illness/mental disorder

This, of course, is the portion of the continuum with which psychiatry has been most directly involved, and I needn’t elaborate, beyond noting a few important elements of mental disorders illustrated in the Figure. First, as we move to the far right of our diagram, the likelihood of “disease-like properties” increases. Specifically, the condition begins to become “clinically significant” and-as the DSM-5 notes-is usually associated with “significant distress or disability in social, occupational, or other important activities.”10(p20) In addition, what I have called “core self-regulatory functions” decline steeply as we move to the far right. This includes the person’s ability to “reality test;” maintain impulse control; engage in rational decision-making; carry out activities of daily living; and-to use Dr Robert Daly’s term-to secure one’s “prudential interests.”13

The more the person’s condition takes on disease-like properties, the greater the dysfunction and disability in these core self-regulatory functions. Finally, as we approach the level of clinically significant psychiatric disorder, we find properties common to disease and disorder throughout general medicine: high syndromal coherence; good inter-rater reliability (kappa); substantial predictive validity regarding course and prognosis of one who meets the diagnostic criteria; familial and/or genetic correlations; characteristic biomarkers or biological abnormalities; and substantial suffering and/or incapacity.14,15

Classic psychiatric disorders that meet all, or nearly all, these criteria include schizophrenia and bipolar disorder.


The central consequence of the continuum described here is that-based on the best available evidence-most mass shooters would not fall into the range of frank mental illness or disorder.2,3 This has critical implications not only for our everyday understanding of mass shooters, but also for forensic and legal determinations; for example, regarding use of the so-called “insanity defense” in cases involving mass shooters. This is not to say that serious mental illness, including psychotic conditions, plays no role in mass shootings. It’s likely that a small percentage of mass shooters do have bona fide mental disorders of psychotic proportions. But most-like our composite character, Tyler-are profoundly unhappy people whose worldview is shaped by “the 3 Rs”: rage, resentment, and revenge.

Accordingly, when we psychiatrists are asked by the media, “How can someone who randomly shoots ten or twenty people not be mentally ill?”, we can reply by pointing out two things: first, that there is a distinction, however nuanced, between PED and mental illness; and second, that horrific violence on a mass scale is well within the range of socially deviant but psychiatrically “non-disordered” human behavior. Tragically, human history tells us that this has always been so.16

Acknowledgment:  Dr Pies would like to thank Dr James L. Knoll for his comments on an earlier draft of this article; Anna Chavez, PhD, for her comments on emotional disturbance; and Dr George Brownstone for stimulating discussion of these issues (personal communication, 8/30/19).

Next > Letter(s) to the editor


by Mark S. Komrad MD

Another beautiful essay. I have long agreed that a continuum is as important in psychiatry as it is in other fields of medicine (e.g. blood pressure, blood sugar, PSA  etc). Frankly, I refer to Humpty Dumpty in Alice in Wonderland: “A word means whatever I want it to mean, no more or no less.“ I think the term “mental illness” (which incidentally isn’t even in the title of the DSM) means whatever people need it to mean in the specific context: clinical, political, advocacy, etc. Of course, without any other domains of validation for our constructs outside of clinical phenomenology, we will have to create workarounds like you’ve made in this article, that refer to “zones“ along a continuum, which is actually a watered down version of “categories.”

In the case, the young man believed :  “I’m the only true-born leader who can purify this world of its filthy elements.”
Many might really see this as a cardinal symptom of grandiose delusions that crosses the line into the psychosis zone. Too bad that we don’t have another domain of validation to make that call, and it’s just one psychiatrist’s opinion versus another  to decide that (which surely  would be exploited in a courtroom).

You posed the common question: “if that’s not mental illness, what is it?“ It might be better posed: “if THAT’s not mental illness, then what IS mental illness?“

Warm Regards,

Mark S. Komrad MD
Faculty of Psychiatry, Johns Hopkins, Tulane, and University of Maryland

Response by the author

Many thanks on the kind assessment of my article, Dr. Komrad. You are raising some critical issues and questions in psychiatric nosology. First, I agree that the continuum/spectrum approach is usually more helpful than an iron-clad, categorical system, when assessing degree and nature of psychopathology. Hence, my diagram.

That said, I do think there is still a place for some categorical diagnoses, such as Schizophrenia, Bipolar I disorder, OCD, Alzheimer’s Disease, and maybe a dozen or so other DSM-5 categories. For these conditions, we generally do have ancillary "validators" besides clinical phenomenology, such as family history; genetic patterns, predictive validity of the diagnosis, response to medication (e.g., lithium for BPD), some “so-so” biomarkers, and, of course, in the case of Alzheimer's, actual brain pathology. But these are really the exceptions that prove the rule.

I actually think we have greater communal consensus on what the term "mental illness" means than would be suggested by our friend Humpty Dumpty!  Although, as you indicate, definitions of “mental illness” (or “mentally ill”) will differ somewhat depending on the context and "need"--legal, clinical, etc.---I suspect that there are "family resemblances" among these variant definitions, to use Ludwig Wittgenstein's famous term. That is, there are common "fibers" that run through most definitions of "mental illness", even though there may be no single feature that all have in common.

The DSM-5, as you say, doesn't use the term "mental illness", though it provides a very broad and "elastic" definition of "mental disorder" on p. 20. (I have always found the term “disorder” to be very sketchy and evasive). One of the best definitions of “mental illness” that I have seen comes from “The Land Down Under.” Specifically, the Australian Law and Justice Foundation defines “mental illness” as:

“…a condition characterized by the presence of symptoms such as delusions, hallucinations, serious disorder of thought form, a severe disturbance of mood, or sustained or repeated irrational behavior, which seriously impairs, either temporarily or permanently, the mental functioning of a person."

Not bad! But, here is where we meet the fly in the ointment: For there will always be disagreement as to what constitutes "serious disorder", "severe disturbance", "serious impairment", etc. We will always have differing notions of how to measure these terms; e.g., "how severe is severe?" etc. This means there will always be debates regarding how high or low the threshold for diagnosing "illness" should be. And in the end, these become pragmatic, if somewhat arbitrary, judgments. In this regard, psychiatry is not radically different from other medical disciplines; e.g., where do we draw the line between a cytologically “atypical” cell and a “malignant” cell? And at what level of systolic and diastolic elevation do we decide someone has “clinically significant” hypertension?
The Australian website also makes the additional astute point:

"Because the focus of clinical practice is on prevention and control of mental illness through treatment, clinical definitions of mental illness are far broader than their legal counterparts. It is rare to find a single definition in the clinical setting: in this context, a definitive statement about what is mental illness is often less helpful than determining how a disorder should be classified and treated." [italics added]

Indeed, that speaks to the pragmatic and therapeutic rationale for diagnosis and classification.

Re: my composite case of "Tyler", Mark: you are right, of course, that his statement ( “I’m the only true-born leader who can purify this world of its filthy elements.” ) could be the kernel of a grandiose delusion. We'd have to "tease out" whether this is just "bravado" in a narcissistic-paranoid personality type-and does that amount to “mental illness”?--or is it a fixed, false belief, impervious to reason or "reality testing"? Unfortunately, we don’t have such fine-grained, clinical data for most mass shooters. 

A number of psychoanalytically oriented clinicians, including forensic psychologist, Dr. Reid Meloy (who co-authored the companion piece with Dr. James Knoll) believe that many, if not most, mass shooters, have a "Borderline Personality Organization" (a la Kernberg) that can veer over into frank psychosis, under certain kinds of stressors. [personal communication, Feb. 19, 2020]. "Tyler" could be one such type. Does that (borderline) personality organization per se constitute "mental illness", if it falls short of the DSM-5 criteria for Borderline Personality Disorder? (Dr. Meloy believes that is likely to be the case). Here, I think we verge on an essentially semantic debate, though it also impinges on the important clinical issue of “threshold” for “disease”, “illness”, etc.

Thanks again, Mark, for your very fruitful and heuristic comments!

Ronald W. Pies, MD


Dr Pies is Professor Emeritus of Psychiatry and Lecturer on Bioethics and Humanities, SUNY Upstate Medical University; Clinical Professor of Psychiatry, Tufts University School of Medicine; and Editor in Chief Emeritus of Psychiatric Times (2007-2010). He reports no conflicts of interest concerning the subject matter of this article.



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