How Bad Is Marijuana for Your Health?

[Skyler]

This is a follow up that to the previous my last post on this topic that addresses many of the concerns expressed by those who responded.

 

"Many stories also claimed that the Gilman study showed direct causation between pot smoking and brain abnormalities. That’s wrong. The study looked at differences between pot smokers and abstainers at a single moment. Only a longitudinal study, examining brain changes over time, could have suggested causation. As a letter writer to the Journal of Neuroscience noted, it’s possible that pre-existing brain differences cause some people to seek out marijuana. Gilman’s pot smokers also drank more and smoked more cigarettes than the control group, which supports this interpretation and also raises the possibility that other factors led to brain structure differences."

 

"The biggest problem with the coverage of the marijuana study was that it failed to put the new research into context. Valentina Lorenzetti of the University of Melbourne recently published a widely cited review paper synthesizing dozens of studies on marijuana and the brain. Taking the literature as a whole, there is evidence suggesting that marijuana use causes structural changes in three parts of the brain: the frontal lobes, temporal lobes, and the cerebellum. The data also reinforces the idea that long-term, heavy smokers experience greater changes than casual users. The studies, however, have serious flaws. They are typically small and have been unable to show that the structural changes cause cognitive impairment. Gilman’s study of 20 smokers is a good contribution to the literature, but it doesn’t resolve those problems." http://www.slate.com/articles/health_and_science/medical_examiner/2014/05/marijuana_brain_studies_comparing_pot_with_alcohol_and_cigarettes_on_health.html

 

PS... I cannot locate the previous post.. my apologies.

[Rhiannon]

Like I said before about this, so many people have an agenda where marijuana is concerned, and it's not a simple subject anyway--it has complex effects because there are lots of different cannabinoid compounds in marijuana, some of which have completely opposite behavioral effects. There are different ways of using it, too--dosage effects, oral versus smoked versus vaporized, frequency of use... Just way too many variables, impossible to control for them all without a very carefully designed experiment.

 

Plus as has been noted many times by different groups, medical "science" is notoriously bad. Maybe less so with marijuana than with more profitable drugs, devices and procedures, but given the agenda issue (some people want to prove it's evil and super dangerous and straight from Satan, others want to prove it's a miracle herb straight from heaven) I suspect we will continue to have a similar problem with this as well.

 

I think it's going to be a long time (if ever) before we get good, solid science and a clear, reliable consensus on the effects, uses, dangers, and gifts of marijuana.

[Skyler]

Hi Rhi.. I appreciate where you are coming from, but I think the synthesis of the studies referenced in this article offers a reasonably comprehensive perspective. I realized the article in the Journal of Neuroscience uses a sample that is too small, and thought this offered a more comprehensive picture. http://www.jneurosci.org/content/34/16/5529.abstract

 

I do not have a simplistic view of marijuana or any other drug as our responses and circumstances are too individual (a post made by me a couple of years back on a different drug was erroneously interpreted in this light, much to my chagrin)... Just now there is such a preponderance of positive references in the media one might surmise marijuana is a panacea for all the ails of mankind, and therein lies my concern.

 

As always, your input and perspective is valuable.

 

"Valentina Lorenzetti of the University of Melbourne recently published a widely cited review paper synthesizing dozens of studies on marijuana and the brain." http://www.ncbi.nlm.nih.gov/pubmed/23829361