There is NO proof of ANY damage or ANY permanent changes caused by raw cannabis or ANY compounds found in cannabis. Even when using nonstop maximized doses that only exist in a laboratory (thousands of times higher than any “high potency pot”). The ONLY proven side-effects are temporary impairment and lung damage (which can be easily avoided with a vaporizer).
EVERY single study hinting at brain changes clearly says “MAY” and merely illustrates a casual statistical correlation. NOT a direct cause.
To prove a direct cause of brain damage, you would have to perform a twin study on animals or humans (the standard for every other drug). Yet, after nearly 80 years of prohibition and over $1 Trillion spent, not a SINGLE set of twin animals/humans has shown ANY permanent difference from ANY dose of cannabis. If it truly was that damaging/altering, prohibitionists would have NO PROBLEM showing a reproducible experiment of twin animals showing ANY difference at all.
Here are some other examples of casual statistical correlation that prove NO direct causation:
Schizophrenics are statistically 2-3 times more likely to smoke cigarettes. This does NOT mean cigarettes cause it.
http://news.sciencemag.org/2008/10/why-schizophrenics-smoke
Men who have had sex with 21 or more women statistically have lower risk of prostate cancer. It does NOT mean having sex with 21 women directly reduces cancer.
http://www.telegraph.co.uk/science/science-news/11192385/Sex-with-21-women-lowers-risk-of-prostate-cancer-academics-find.html
But it can't hurt to try. ;-D
You only read the articles that agree with your conclusion.
http://www.medicaldaily.com/marijuana-use-causes-brain-damage-confirmed-241869
Scientists from MCRI, Melbourne University and Wollongong University compared MRI scans of the brain for 59 people who had been using marijuana for an average of 15 years to 33 healthy people who had never used the drug.
After measuring changes to the volume, strength and integrity of white matter in the brains of all participants, researchers found that long-term heavy cannabis users had disruptions in their white matter fibers.
By the way, did you know that the age when you start smoking cigarettes is more significant than when you stop? People who started smoking in their early teens were more likely to get lung cancer than those who started later in life. My mother-in-law was a great example of this, she started at 12 and stopped at 50, but died of lung cancer at 89.