Well it's the age we live in, young people want to have as much fun as possible because according to most, "You only live once". The thing is that drugs and narcotics are part of what they refer to as "fun so it shouldn't be surprising that the use of drugs has increased over the years.
Social media and celebrity icons haven't helped matters in the sense that they themselves use drugs and their followers and people who idolise them often walk in their footsteps. Young people these days, in fact in almost any age have always wanted to have fun, to dance and to enjoy themselves. Over the years, the parties have gotten wilder and the fun has grown to include drugs.
Drug abuse is on the increase because youths today don't really care about their futures, alot of them cling to liberalised beliefs which end up doing more harm than good to them on the long run. The truth is that alot of them know what they're doing but they don't care, they're having fun.
Peer pressure might be another reason why it's increasing because even people who don't normally do drugs are getting pulled into that life because they have friends who do it, and by the time one person brings one person who brings another, the drug abuse just keeps on increasing.
As far as reducing it, I think the best thing to do would be to focus on preventing the next generation from following the same path as the previous one. For this present generation of youths, the best thing to do would be to impose stiffer punishments for drug abuse. Hopefully it will serve as a deterrent. Countries like Malaysia give the death penalty for using or selling drugs and it didn't really reduce the rate of drug abuse, but then again it might be different in another country, it may or may not work, but it's the best thing that can be done.
I hope this helps.