Cannabis used to be relatively harmless, but the skunk that's in use today is highly dangerous. As has been said, it can drive you nuts. But, like everything else, it is a conscious choice.
Conscious choice maybe, but not an informed one. When I was teaching, I invited a member of the local Drugs Watch team to give a talk on drug abuse. He started by asking if the students thought that cannabis was harmful. Most considwewd it to be as "safe" as tobacco.
He then proceded to show slides of the physical effects of smoking weed - mainly on the gonads! He described in graphic detail how considerable shrinkage and ulceration would take place, rendering them unable to father children and possibly lose their manhood altogether.
The students resolved to give up smoking weed!
That's what I meant by informed choice......
Ron.