David Frum has obviously never smoked pot:

After horrific shootings, we hear calls for stricter regulation of guns. The Tucson shooting should remind us why we regulate marijuana.

Jared Lee Loughner, the man held as the Tucson shooter, has been described by those who know as a “pot smoking loner.”

He had two encounters with the law, one for possession of drug paraphanalia.

We are also learning that Loughner exhibited signs of severe mental illness, very likely schizophrenia.

The connection between marijuana and schizophrenia is both controversial and complicated. The raw association is strong:

* Schizophrenics are twice as likely to smoke marijuana as non-schizophrenics.
* People who smoke marijuana are twice as likely to develop schizophrenia as those who do not smoke.

But is correlation causation?

Jared Lee Loughner may or may not have mental health issues, in many ways his rants are similar to a Tea Party speech or possibly an early draft for a post at Reason, but I’d be hard pressed to make the leap from smoking dope to mini-mall shooting spree. Then again, if people are willing to believe that crosshairs are actually the more commonly used “surveyors symbols“, I suppose any belief no matter how far-fetched, desperate and idiotic is as valid as another.