It would be wonderful to be able to predict and prevent mass shootings such as those that occurred in Jacksonville, Florida, Aurora, Colorado, Las Vegas, Sandy Hook, Connecticut, Parkland, Florida and elsewhere. But as much as people want to think that criminal investigations, trials, psychologists and psychiatrists can lead us to prevention, or determine a straightforward “why” for most mass killings and their perpetrators, they can't.

There is no "magic bullet" for identifying future mass killers, and certainly not one associated with my specialty of psychiatry. The difficulty is that, as much as we can describe the traits that most mass killers have in common, they aren’t useful as predictive tools.

For instance, almost all of those who have killed large numbers of people are males. Over half (in the U.S. and Canada) are Caucasian. Half or more have a diagnosable mental disorder. Close to 100 percent eat meat.

I'm not trying to be cute; I'm making an important point. It makes sense to look for factors, such as a recent history of severe violence, that contribute significantly to individual risk, but it is illogical to point the arrow of causation backward toward large population groups. Millions of times more mentally ill North Americans don't commit mass killings than do.

It is inaccurate and patently unfair to the 20 million or so diagnosably mentally ill people in North America to suggest that mental illness per se is at the root of mass killing — or any killing except suicide, for that matter. Very large and well-designed studies show over and over that the presence of mental illness in itself (excepting substance abuse) is neither a predictor of nor risk factor for violence, and certainly not lethal violence. I am far more worried about potential harm from "ordinary" criminals, abusive spouses, people impaired by alcohol, amphetamine and heroin abusers and sleepy drivers.

A better understanding of mental illness and an improved mental health care system would help millions of Americans, but probably wouldn’t do much to reduce the murder rate or violent crime in general. More flexible civil commitment laws, to allow hospital­ization and treatment against a patient’s will, might. That would help tens of thousands of patients every year and prevent a few crimes and many suicides, but the societal tradeoffs between the need for clinical intervention to protect people from harming themselves or others and a person’s right to refuse care and involuntary hospitalization are complicated, at best.

"A Dark Night in Autora," by Dr. William H. Reid. Skyhorse Publishing

For individual cases — almost always viewed after the fact and clouded by social outrage, finger-pointing, media frenzy and political posturing — improving our mental health care system is certainly worth discussing, but our greater aim should be to advance care, and access to care, for the millions of patients who aren’t destined to be violent.

I am not, of course, suggesting that we ignore danger signals in psychiatric patients; indications of danger should be taken seriously whether the person is mentally ill or not. But even as recognizing risk in threatening statements and behaviors is important, it’s important to note that many people, in every demographic, make threats. Some — which is still lots of people — go on to violence. Virtually none will ever commit a mass killing.

So recognizing and stopping the tiny handful of future mass shooters in North America and the world isn’t really about improving mental health care — though that’s important on its own — or perfecting the actions of law enforcement. Such killings are not, in any realistic sense, “the system’s” fault.

The real reason that someone commits a mass killing usually lies within some an unimaginably detailed, idiosyncratic (not group-associated) conflu­ence of factors that we can’t replicate because it is incredibly rare; on top of that, we can’t see all of those factors. Every case is an almost-unique condition that arises in only one person among millions, and the few people in whom it arises usually hide it well (sometimes even from themselves).

It’s nonetheless very tempting to resolve the enigma of things like James Holmes’s Aurora theater shootings by creating an easy explanation, one that sounds good to people who reflect our views back to us in conversation or on social media. Such a “why” doesn’t have to be accurate or tell the whole story; it just needs to create the impression that the “why” is settled.

We want simple; sometimes we need simple. That’s why some people arrive at so-called "explanations" like a "Zoloft® hypothesis," or a government frame-up hypothesis, a spurned-lover hypothesis, a “pure evil” hypothesis or even a psychiatric one.

Most of the "explanations" to which we’re drawn aren’t so much explanations as they are resolutions: They’re ways to resolve our frustrations, our fears and even some unconscious feel­ings, but they don't really explain anything, and they don't fix the problem.

Dr. Reid was one of two psychiatric experts retained by the presiding judge in People of the State of Colorado v. James Holmes, and the only psychiatrist allowed to record interviews with Holmes.