Time Magazine’s website today posted an article by Nathan Thornburgh on the killings in Arizona titled “Why Are The Mentally Ill Still Bearing Arms?” As of this morning, it was the second most-read article on Time.com.

The title of the piece — and its text — state as fact the reason Jared Loughner killed six people and wounded 13, including U.S. Rep. Gabrielle Giffords, in Arizona on Saturday: Loughner is mentally ill.

The media has always been too quick ascribe assassination attempts and murders to mental illness. It handily fills in he “why” in the 5 W’s; it blithely explains the inexplicable. And it is wrong, factually and morally.

Loughner may indeed be mentally ill, but mental illness in and of itself is not a motive for or a cause of murder. According to data from the National Institute of Mental Health, a little more than 4 percent of American adults, or about 12.4 million people, have a “serious mental illness.” They are not all potential murders.

The media’s use of mental illness to explain violence that is inexplicable shapes the public’s perception of why a murderer kills. Here are two tweets (I will not attach the names) from the Twitter stream of the trending topic “Jared Lee Loughner”:

It’s irrelevant whether Jared Lee Loughner is left-wing nut or right-wing nut. Bottom line is, he’s crazy, pure and simple.

Let’s be clear. Jared Lee Loughner is neither a liberal nor a conservative. He’s a whack job.

Thornburgh, in his Time article, even provides a diagnosis of Loughner’s mental illness:

Gun-control advocates may see the Tea Party protesters as the face of provocation, but it’s the quiet, grim paranoiacs like Loughner who represent the real danger. [emphasis added]

Paranoid schizophrenia has been, over the past 48 hours, the most popular diagnosis of Loughner made by people who should know better than to diagnose based on YouTube videos.

U.S. Sen. Rand Paul, an ophthalmologist, told Fox News, “From a medical point of view, there is a lot to suggest paranoid schizophrenia.” A Fox National blogger made the same diagnosis. So did a psychologist on the popular blog Firedoglake.

If Loughner is in fact a paranoid schizophrenic, he is among the 1.1 percent of American adult — or 3 million — who undergo schizophrenic episodes in a given year. I’ll say it again: They are not all potential murders.

A few voices have publicly objected to this rush to diagnosis and this facile connection of mental illness to murder, none as lucidly as Vaughn Bell, an English clinical and research psychologist and writer (he authors a blog called Mind Hacks), did yesterday in his piece for Slate.com.

Severe mental illness, on its own, is not an explanation for violence, but don’t expect to hear that from the media in the coming weeks.

Numerous studies show that crimes by people with psychiatric problems are over-reported, usually with gross inaccuracies that give a false impression of risk. With this constant misrepresentation, it’s not surprising that the public sees mental illness as an easy explanation for heartbreaking events. We haven’t yet learned all the details of the tragic shooting in Arizona, but I suspect mental illness will be falsely accused many times over.

I suspect, alas, he suspects rightly.

Follow Mark Leccese on Twitter at @mleccese.