I have lots of studies and resources on my drive but really no way of uploading them, however when I was doing a term research paper last semester I bought this book http://www.amazon.com/Pot-Book-Complete-Guide-Cannabis/dp/1594773688 and it basically saved my ass. It is the most complete book on the cannabis plant and the culture that I know of. The woman who compiled it is awesome, all the citations are already done for you in the back of the book. Your research is basically done if you get this. Plus it's really fun to read.
I was under the impression that the main difference between then and now is the fact that most females are grown in seclusion from the males and thus produce the large, frosted, stanky buds we've come to know and love. The females are sexually repressed on purpose!
Also, I think NIDA figures report an increase from about 4% to 7% THC/plant mass from mid 1980s to present.
src: http://www.amazon.com/Pot-Book-Complete-Guide-Cannabis/dp/1594773688
I was just gunna say google but there are a few books I can think of.
http://www.amazon.com/The-Pot-Book-Complete-Cannabis/dp/1594773688
http://www.amazon.com/Marijuana-Horticulture-Outdoor-Medical-Growers/dp/187882323X
That's a lie, which is why you didn't bring out any supporting evidence.
This is a part of a drug war campaign to make people believe that psychedelics and cannabis contribute to psychosis, when in fact they're medicines that help people like 99% of the time.
There's a chapter in Julie Holland's book "The Pot Book" that analyzes the many studies on cannabis and schizophrenia. I read the entire chapter, and the evidence is very mixed, but overall comes down on the side of cannabis being a good thing. All I'm asking is for the troll brigade to tell the truth, and you can't do it. It is not a rare schizophrenic that does well on weed; it's actually insanely common for people to use cannabis to ameliorate such symptoms. (often they overuse it, imo)
This book: https://www.amazon.com/Pot-Book-Complete-Guide-Cannabis/dp/1594773688