I usually agree with Martin Longman, but I have issues with his March 29 post, “All Mass Shooters Are Mentally Ill.” He writes,

If you decide, for whatever reason, to kill a bunch of strangers, there’s something wrong with your brain. I’d say that you’re ill. We can debate whether individual shooters know right from wrong and just want to do wrong, or if they’re too mentally impaired to realize that what they’re doing is immoral and illegal. In other words, insanity can be a defense in some cases. But it seems wrong to ask whether or not these people are mentally ill. Of course they are.

I’m not a psychiatrist, but I don’t think Martin Longman is, either. Most of the articles by mental health professionals I’ve seen on this subject say that most mass shooters are not mentally ill. See, for example, “Stop Blaming School Shootings on Mental Illness, Top Psychologist Warns” and “Experts Say There’s Little Connection Between Mental Health And Mass Shootings.”

Regarding “there’s something wrong with your brain” — maybe, maybe not. There are some kinds of mental illness, such as schizophrenia, that can be diagnosed by brain scans, but my understanding is that brain researchers can’t yet sort mass killers from not mass killers using current diagnostic tools.

One neuroscientist doing research into brain configurations thought to be associated with violence was disconcerted to find out that his brain exhibited those same configurations. So, while there may be something to his finding that low activity in the orbital frontal cortex is connected to violent tendencies, that’s not a reliable predictor of anything.

Science aside, popular ideas about what constitutes aberrant behavior signifying “mental illness” often is more about sociology than psychology. For example, there’s a strong correlation between gun violence and a history of domestic abuse, but I have yet to see widespread shrieking that domestic abusers must be “mentally ill.” I guess men who abuse women aren’t aberrant enough yet.

Are Klansmen and lynchers “mentally ill”? Are young  people who run away to join ISIS “mentally ill”? What about Dylann Roof, who’d been raised to be a racist? There’s an article at WaPo about some loser kid still living with Mama with no job, ambition or prospects who has become a neo-nazi, and frankly if he were mine I would have drop-kicked his ass out of my house. Is he “mentally ill”? He’s maladjusted, certainly. Is social maladjustment the same thing as “mental illness”? In which case, who among us doesn’t qualify, at least part of the time? The only difference between “normal” and “pathology” would be a matter of degree.

Three years ago I wrote a post titled “Are Guns Nuts Too Mentally Ill to Own Guns?” I intended the title to be tongue in cheek. But what I had found is that researchers were finding a correlation between men exhibiting angry, impulsive behavior and the ownership of multiple firearms. And men exhibiting angry, impulsive behavior who own multiple firearms are much more likely than other people to become mass shooters. But they don’t all become mass shooters. No psychiatrist can predict with any certainty which of these guys are mostly harmless and which will be the next Stephen Paddock, or which brooding, maladjusted teenager will run off and join ISIS, shoot up his school, kill himself, or straighten up and become an accountant.

In the case of the angry, impulsive gun owners, even if they were compelled to undergo some kind of psychotherapy, unless they want to change (which would be rare) it’s not going to work. Maybe if you kept them on a strong enough dose of Diazepam they’d be less likely to be violent, or at least be easier to get along with. But then they wouldn’t be able to drive cars or operate heavy equipment, either.

“Insanity” is a term found only in law, not in medicine. The idea is that someone who is “insane” is not responsible for his acts and may be found not guilty of a violent crime. But that’s rare. Severely psychotic people, whose thoughts are so scrambled they really don’t know reality from fantasy or right from wrong, generally don’t commit violent crimes, if only because they also tend to be too mentally disorganized to make and carry out plans. Some of our mass shooters, notably Jared Loughner, James Holmes and Adam Lanza, arguably were sick enough that they should have been confined to some sort of group home where they could be monitored. Lanza’s case was particularly tragic in that he’d had a psychiatric workup that recommended a course of treatment, but his parents refused the recommendations. And then his mother kept him at home and catered to his symptoms in a house full of firearms.

So, yeah, sometimes they are “mentally ill.” But most of the time, they aren’t “ill” with anything there’s any treatment for, or that all kinds of other people who don’t become mass killers don’t have also.

So, the “mental illness” label isn’t telling us anything useful. It doesn’t give up actionable information that will sort the mass killers from the general population before they start shooting. But it does (in some people’s minds) provide a handy-dandy excuse for arguing that guns aren’t the problem. But there are crazy people in other countries, too, and somehow they have much lower rates of gun violence. Because they have a harder time getting guns.

See also Guns are responsible for the largest share of U.S. homicides in over 80 years, federal mortality data shows.