Wednesday, March 9, 2011

Cannabis Use: Is It Really Safe? Part 2

I believe in trends, not fads.  So unless the first study suggesting a change in management is really strong (statistically significant, causative data rather than just associative, in a similar population, looking at clinical outcomes that matter rather than just disease risk markers), I tend to wait for follow up studies with similar findings.  In science, we've been burned too many times by some remarkable & miraculous discovery, only to find out later that the results were conjured, as no one else has been able to corroborate the outcome.  In medicine, we say "Never be the first, but never be the last".

Along those lines, when I stumbled upon an article in the USA Today over the weekend, I thought I had managed to trump them but as I read further into the article, I realized that the tables had been turned.  Instead, I had missed an article published in the British Medical Journal last week and was looking at more evidence linking cannabis to psychosis (remember my post from two weeks ago?).

The authors had followed a cohort of 1923 individuals over a decade and noted that, in those participants without baseline history of psychosis (or psychotic symptoms) and no admitted cannabis use ever, initial use of cannabis over the ensuing 3 years almost doubled the risk of psychosis during the next 8+ years.

As a family physician & geriatrician, not a psychiatrist, I find it compelling that I have now found 5 studies published in reputable journals over the last 4 years linking cannabis to psychosis (not to mention a number of other health conditions).  Maybe it's time we took another look at this billion dollar industry.

Part 3
Part 1

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