I wonder, if you hold other psychoactive substances - say coffee, alcohol, or nicotine to the same standard?
That is, we should assume they cause long term impairment without the need for any kind of study?
That is, we should assume they cause long term impairment without the need for any kind of study?
If a study comes back and says, with a high confidence, that isn't the case for this or that, great, but I think it's a safe assumption for most chemicals.
Edit: Just to be clear, I'm saying it's not enough to show something is bad, as pretty much everything is bad. It has to be bad enough to matter.
I think we are mostly in agreement - that any substance entering the body will have some effect.
The question is what effect, how much of an effect, and wether it is permanent/long lasting. Questions which require a study to answer.
Unless we're able to find twins that live largely the same lives absent the one factor, we are really only capable of sussing out the especially harmful things with long term lifestyle studies. If cannabis is as bad as sugar, then we have 40 years of back and forth to look forward to, and the answer will ultimately be: A little bit is bad, but not bad enough to matter more than how many steps you took today, or how sad or angry you were, or how late you ate dinner.
Alcohol is clearly capable of long term impairment, the debate seems to be about dose response. Nicotine is more questionable, but clearly leaves long term changes in the mind. People abstaining after long term nicotine usage will spend the rest of their lives experiencing cravings. Hell, it seems plausible long term consumption of food types has long term cognitive effects.