From a comment on slashdot - I'm not American, but this sounds quite plausible to me:
http://news.slashdot.org/story/15/11/27/1343243/lsd-microdosing-gaining-popu... " If you're a $100k/yr engineer (Score:4, Insightful) by rsilvergun (571051) on Friday November 27, 2015 @10:52AM (#51013395) such things don't apply. In America we have a multi-tiered justice system. It's pretty well documented. Wealthy and educated people get treatment programs, while poor (and let's face it, black) people get jail. It's because what we're really using our drug policy for is to keep the poors in check. Think of it this way. If your poor chances are you or one of your friends is using drugs to cope with poverty. Now, our drug laws, in particular our asset forfeiture laws are basically guilt by association. Combine that with juries that are inherently conservative (since you generally have to be well off to be able to afford to server on a jury for any length of time). So when poor people show up in wealthy neighborhoods they not only stick out like a swore thumb, but odds are good the cops can bust them for the drugs at least one of them is carrying. This keeps poor people out of wealthy school districts and parks, and lets the wealthy enjoy their (much, much better) public services. Basically, our drug policy is central to maintaining our class divide... "