I think that the big part of the drugs problem, is that young people are trying it before they become adults.
The parents are always worried about this, and they demand to not make drugs legal, and they want to protect their kids right?
But forbidding them makes only things worse.
The crime gangs are more and more powerful thanks to the money from drug business, civils have to contact with criminals to get weed or cocaine.
After that, they may go to jail for possesion, which is a very stupid thing.
Why the society needs to pay for someone who is taking drugs?
That is an adult, so he is on his own, we shouldn't punish him for taking something he want to take, even when the law forbids that.
Young people are supposed to test things, but a young person usually has some education they get from their parents which affects all of their actions. A good parent does not protect their kid by asking the government to make rules for them when they are adults.
Also, if you look at the best people in society, they are usually the ones who made the worst mistakes, then learned for themselves. So even if a kid utterly fucks up his or her life, there is a chance they might be one of the few who end up smarter than anybody.
The best medicines are made from the worst poisons, but a person has to be smart.