I’ve written previously about the mainstream media’s propensity to under report and distort stories that challenge marijuana prohibition.

Apparently my latest missive has hit a nerve — as it has quickly risen to become the most read story on Alternet.

5 Things the Corporate Media Don’t Want You to Know About Cannabis
via Alternet.org

1. Marijuana Use Is Not Associated With a Rise in Incidences of Schizophrenia

2. Marijuana Smoke Doesn’t Damage the Lungs Like Tobacco

3. Cannabis Use Potentially Protects, Rather Than Harms, the Brain

4. Marijuana Is a Terminus, Not a ‘Gateway,’ to Hard Drug Use

5. Government’s Anti-Pot Ads Encourage, Rather Than Discourage, Marijuana Use

Read the full text of the story here.

[Editor's note: This post is excerpted from this week's forthcoming NORML weekly media advisory. To have NORML's media advisories delivered straight to your in-box, sign up for NORML's free e-zine here.]

The consumption of cannabis, even long-term, has a “minimal” impact on brain function, according to a systematic literature review just published online by the journal Psychological Medicine.

An international team of investigators from the United Kingdom, Spain, Brazil, Australia, and Switzerland conducted a systematic review of the effects of cannabis on brain structure and function.

Authors wrote, “We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. … Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. … Only three of the structural imaging studies found differences between users and controls.”

Investigators concluded, “Minimal evidence of major effects of cannabis on brain structure has been reported,” noting that marijuana users and controls perform similarly on cognitive tasks.

According to a 2001 study published in the journal Archives of General Psychiatry, long-term cannabis smokers who abstained from pot for one week “showed virtually no significant differences from control subjects (those who had smoked marijuana less than 50 times in their lives) on a battery of 10 neuropsychological tests.” Investigators added, “Former heavy users, who had consumed little or no cannabis in the three months before testing, [also] showed no significant differences from control subjects on any of these tests on any of the testing days.”

Ever wonder why the studies purporting to ‘prove’ marijuana’s health risks only recruit subjects who smoke pot 24 hours a day, seven days a week?

Heavy marijuana use shrinks brain parts
via Reuters  

Brain scans showed the hippocampus and amygdala were smaller in men who were heavy marijuana users compared to nonusers.  … The men had smoked at least five marijuana cigarettes daily for on average 20 years.    

The answer: If they didn’t, there wouldn’t be any purported risks left to write about.

I mean, seriously, imagine if these scientists had tried recruiting 15 subjects who drank at least five shots of vodka every day for 20 years? That is, if they could find 15 subjects who were still alive.

Marijuana may up heart attack, stroke risk
via Reuters

Heavy marijuana use can boost blood levels of a particular protein, perhaps raising a person’s risk of a heart attack or stroke, U.S. government researchers said on Tuesday. …The marijuana users in the study averaged smoking 78 to 350 marijuana cigarettes per week.

The study did not look at whether the heavy marijuana users actually had heart disease. 

So here we go again. Three-hundred and fifty joints per week?! Who are these people? And what’s with the caveat at the end of the story? If the purpose of the study is to assess whether there might be a link between ridiculously heavy pot use and heart disease, then why not, you know, look to see whether the subjects actually suffered from heart disease? (Likely answer: Aside from the abnormal protein level, the patients were probably otherwise healthy.)

Bottom line: smoking pot all day, every day probably isn’t good for you (though I find it interesting that, even among the most prolific pot users, most of the herb’s purported dangers are either speculative or are only apparent on hyper-sensitive brain scans and multi-tiered neurocognitive tests). Fortunately, 99.9 percent of pot smokers don’t behave this way.

And no, it’s not prohibition that curbs their use habits; it’s the recognition that too much pot is not conducive to an otherwise healthy, responsible lifestyle (just as pounding five shots a day wouldn’t be conducive to, well, life).

So what lesson can be learned from the two studies above (aside from the fact that our government has no interest in investigating the health of ordinary cannabis consumers)? It’s that pot, like alcohol, is best consumed in moderation, and that pot prohibition — even when compared to the excessive use of the drug itself — still poses the greatest threat to health.