what a bunch of Bull shit. Its funny how people and politicians know so very little about cannabis but profess to know as much as possible to create guide lines which are not supported by scientific studies. 1st Abstinence, as people  grow older our endocannabinod system degrades and CBD's are not being produce causing things like memory loss and other degenerative brain functions including dementia. https://www.algemeiner.com/2017/05/11/cannabis-could-cure-dementia-says-joint-israeli-german-study/  2. Don’t use marijuana at a young age, it is much better for the medical community and the pharmaceutical corporations to push drugs like Ritalin, but studies confirm  no link associated with teen IQ with usage. http://www.sciencealert.com/extensive-twin-study-finds-no-link-between-marijuana-use-and-iq-decline-in-teens