Cannabis seems to be normalised and many people don't even consider it a drug. My brother-in-law is a psychiatrist and he says that he fears legalization in the UK as it would increase
In his 20 years of work, he says that the patients who only used, alcohol, or prescription drugs had a far better outcome for their mental health than those who smoked cannabis regularly (apart from the addiction) who regularly visited after suffering a psychotic break.
Cannabis is obviously far safer in terms of physical health than other drugs and not everyone gets the bad effects, but people seem to downplay the potential harm it can cause if you're predisposed to psychosis/schizophrenia.
If I think back my childhood, I went to a high achieving private school were many people I knew dabble in all sorts of drugs and it seemed that even among the excessive users, those who used cannabis and didn't develop psychosis still fared worse in terms of academic achievement than those dependent on alcohol who usually reduced their drinking as they age.