New Study: Marijuana Does Not Cause Psychosis, Lung Damage, or Skin Cancer
Posted in Chronicle Blog by Scott Morgan on Thu, 08/02/2007 - 12:03am I've performed a meta-analysis of various scare stories about marijuana appearing in major papers this week. The results of my research are as follows:
Alarmist reports about marijuana will turn out to be wildly exaggerated and in some cases completely fictitious. Obvious inconsistencies will be overlooked by the press and widely available contrary evidence will be ignored.
I read various stories about marijuana and used basic logic and reasoning to determine whether their conclusions made any sense. In some cases, I used Google and other sources to search for other information that contradicted seemingly dubious claims.
Marijuana Increases the Risk of Psychosis by 40%: This one turned out to be totally wrong. Apparently a correlation between marijuana use and psychosis doesn't necessarily mean that marijuana caused the psychosis. Many of the researchers made this clear in their findings, but reporters left it out. Furthermore, none of the stories on this topic explained that the risk of psychosis is small, so a 40% increase isn't that significant to begin with. Reporters also failed to observe that massive increases in marijuana use over the past century have not corresponded with increased rates of psychosis.
Smoking a Joint is as Bad For Your Lungs as 5 Cigarettes: This report also turned out to be almost entirely bogus. Shockingly, "air flow" was the only category (of several) in which marijuana was determined to be more harmful. Researchers stated that marijuana was 2.5 to 5 times more harmful than tobacco in this category, which reporters simply rounded up to 5 for the headline (behold the lofty journalistic standards of Reuters). Reporters also failed to mention conclusive research proving that marijuana does not cause lung cancer; a notable omission since "bad for your lungs" likely implies cancer for many readers. Finally, media reports failed to explain that marijuana users consume far less per day, and do not continue using for nearly as many years as tobacco smokers.
Marijuana May Cause Skin Cancer: I don't know anything about skin cancer, so I won't attempt to refute the findings of this Harvard study. The manner in which it was reported, however, leaves much to be desired. The FOX News headline reads "Study: Marijuana Use May Cause Skin Cancer." Only upon reading the article does the reader discover that only one extremely rare form of skin cancer has been associated with marijuana, and that the researchers claim that more research is needed. Furthermore, only people with weakened immune systems are even susceptible to this infection. A more appropriate headline would have been "Study: Marijuana May Cause Skin Cancer Under Very Rare Circumstances."
Reading coverage of marijuana research in the mainstream press increases the risk of becoming misinformed by 50-300%. More research is clearly needed to identify further sources of flawed marijuana reporting. The risk of bad reporting remains stable despite concerted efforts to inform the media that hysterical claims about marijuana frequently lack scientific merit. Exposure to poorly researched news about marijuana is correlated with support for costly, ineffective, highly punitive marijuana laws.