I think it could be highly likely that there is a link between heavy cannabis use and delusional thought patterns due to the way cannabis affects memory and perception, but there also is a cultural link between cannabis use and "conspiracy theory" type beliefs as well. Whether it has to do with the drug itself, imo it seems people who smoke weed are much more open to nontraditional ideas about the government. What I mean by that is my friends who smoke weed would for the most part not be considered a republican or democrat. Then again, that is from my small view of the world. Personally I think it hard to deny rampant corruption in virtually all large government and this is due to how closely tied industry(money, big business), power(military, economic), and government is tied. I don't however believe that the Earth is hallow and there are Nazi aliens living in the center. A conspiracy to put simply is more than on person planning to commit a crime in secret. If you get busted with intent to sell, you will also likely get conspiracy to sell drugs or some sort of conspiracy charge. So that being said, I don't think it logical to lump in beliefs such as 9/11 being a highly sophisticated operation(and not the act of a dozen or so half-witted terrorist)- a belief in which there is documentation upon documentation compiled by doctors of all trades like physicist and so on, to be lumped in with a belief like aliens are real and they are using mind control to control the government, or any other completely irrational and unfounded belief about how or why things may work they way they work.
There are huge amounts of people who believe in some ridiculously crazy shit and don't smoke weed. Without trying to single anyone one group out, take a look at your wide array of religions out there and try to tell me that some of those beliefs are not WAY fucking crazier than any ridiculous claim about aliens and governments. I believe there is a cultural link between smoking weed and just questioning things in general, including the mindset that you were raised with. I have a two friends, for example, who grew up going to church of similar beliefs and denominations. One started smoking weed in college and immediately quit believing in the religion he was raised to believe in. The other still goes to church and has continued his path of behavior without question- and in many ways would be considered more "successful" than my weed smoking friend. I think where a lot of confusion can occur is when you start pushing the boundaries of what may be true and false. Religious people tend to be "born" into their belief, then spend their adulthood deepening their belief without question of the initial belief, or if questions within arise they tend to search for ideas that will back up and strengthen their original belief. This I believe is caused for many reasons but the primary being survival and pride. The big difference between them and say a college student recently turned stoner is that the newfound stoner has likely questioned a lot of his original beliefs to get to where he is at, the most obvious likely being that "drugs are bad". So the path can begin at a simple divergence such as "maybe drugs are not bad, or as bad as they say" and continue to "what else is not true that 'they' has said" and so on.
that all being said, stoners are not the only ones to question themselves and their surroundings but a lot of them tend to hold beliefs that would suggest that they are. If smoking weed was the thing that triggered them to think for themselves for the first time, it is likely that they will think everyone should smoke weed or remain ignorant to the truth. Perhaps love them from a distance if you being around them all the time is burdensome. I have friends just like that who I'll hang out with on occasion but more than that and it's not good for me.
I mean they believe in every single one! 8(
