besides one thing they may not have accounted for is
1. Those that smoke weed are more likely to drink alcohol (which WILL kill brain cells on a greater scale)
"Having taken into account other factors such as alcohol or tobacco dependency or other drug use, as well the number of years spent in education,"
2. The study was 1,000 people from a specific geo graphic location. Not only are the numbers on the low side (another survey about weed and its affects of cancer was about 40,000+ I think if I remember correctly) but also it is a different region with a different culture.
This was a study that followed people's lives over 25 years. A survey is nothing but a correlation-type study which means very little to the scientific community (Correlation =/= Causation). This is also a important study because it gives other scientists reason to invest the time and money in their area. You don't start studies on a worldwide scale, no one would fund such a costly study without these types of studies to prove they are worth the money.
3. How early are these teens starting to smoke?
This should have been stated in the article but remember this is a new report of the study. They actual study should clarify this.
All in all teens should not smoke or drink in general as it will affect their brains as they are still developing. I agree partially with the study in that regard.
If so what is the that magic age where people can start to smoke?
"It is such a special study that I'm fairly confident that cannabis is safe for over-18 brains, but risky for under-18 brains."
no scientific evidence was brought forward in this study which makes it just a theory based off of statistics
A theory backed by a 25 year in-depth study. There is more to this report than the page wrote by the news. Do not discount the report based on what someone else writes about it. If you read the paper/report and have the same issues with it I'd be shocked it even got press.
What would you consider Scientific evidence? (Seriously)
I don't mean to be mean nor am I trying to insult you. I have had a good deal of experience with psychological research and just wanted to help people understand what was actually going on. You actually raised questions I could respond to!