with the exception of cannabis. According to the NIDA, cannabis usage among teens has not been this high since the 1980s.
The survey reported that 39.5% of 12th-graders see regular marijuana use as harmful; thats down from 44.1% last year, and lower than the rates from the last two decades. Those numbers are troubling to the institute because previous survey data shows an association between softening attitudes and increased use of marijuana, the agency said.
Our issue around marijuana is a gradual undermining of social disapproval and a perceived harmfulness of its use," (Dr. Wilson Compton, deputy director of the National Institute on Drug Abuse, a part of the National Institutes of Health) said in an interview.
http://www.latimes.com/science/sciencenow/la-sn-pot-teens-20131218,0,4063336.story#axzz2nrkyfIgL
A study in May, done by the Partnership for a Drug-Free America, showed that only 26% of students surveyed agreed with the statement In my school, most teens dont smoke marijuana, though 37 percent said the same in 2008. The May survey noted 71 percent of teens say they have friends who use marijuana regularly, up from 64 percent in 2008.
So, yes, it looks like drugs have fallen out of favor, but herb has not.
However, I would expect to see something like this as cannabis is first legalized because of the novelty. Then it will be boring and a lot of people will stop - and people generally stop or greatly reduce consumption when they have kids and find employment with greater responsibilities.
One argument for legalization is to make cannabis "boring" by mainstreaming it.