This is not true. This matter has been thoroughly studied - have you a source to back up this claim?
Even though the drugs that are often consumed in poor neighborhoods are more likely to be criminalized, they are still used at comparable (and sometimes higher) rates in affluent neighborhoods (along with many other drugs in configurations that aren't prohibited).
I don't understand what you are asking me to source - you are the one making the claim.
Here's an easy read that lays this stuff out plainly (I already linked it from my other comment, below):
http://www.huffingtonpost.com/kim-farbota/black-crime-rates-...
Are you aware of the blue eyes/brown eyes experiment by teacher Jane Elliott? https://en.wikipedia.org/wiki/Jane_Elliott
In any event, the problem, if any, is cultural and economic, NOT racial. I lived with a white Irish guy who grew up in an entirely black neighborhood, and if you closed your eyes you would have zero doubt he was black. One of the coolest (and most mind-blowing) guys I've ever met.
Have you read "Night" by Elie Wiesel? https://en.wikipedia.org/wiki/Night_(book) The Nazis had plenty of correlations (I'm sorry, _FACTS_) to being Jewish, put it that way... and we all know how that ended up.
The only racial correlative that makes any sense to track, to me, is sickle-cell anemia, because it is helpful.
The problem is your brain (and my brain, and everyone's brain). As soon as you learn of an unfortunate correlation with race (or sex... did you know almost all rapists are men? Did you know most people interested in math and science are male? Etc.), you tend to lean on it too much to make judgments across ALL of the correlate, and therein lies the serious problem, because the outliers get _the_shaft_. The well-meaning black man experiences bias on a daily basis and gets worse jobs, the science-interested woman gets scoffed at and thus discouraged by male teachers, and the good gentleman never gets the girl because she crosses the street before actually meeting him out of fear.
So, fucking quit it, man. It's not helpful, in any way, shape, or form. It is disingenuous to all humans, to restrict a handful of them based on a correlation with a physical attribute. It's giving in to the laziness of your brain trying to oversimplify a complex world. It's actively evil, in fact, the equivalent of grouping all Koreans together and calling them "gooks" because the idea that you're shooting actual humans is just too distasteful a thought.
Don't you see? It's ENTIRELY easier for you to not hire an entirely qualified black man, if you're spouting this bullshit.
The reason I mention it is that on average black people tend to be poorer and live in worse neighborhoods, and poor people in bad neighborhoods (of all races) tend to do more drugs. So my expectation would be black people tend to do more drugs than white people, but I still doubt it's enough of a difference to explain the difference in prison population.
http://www.businessinsider.com/heres-median-income-in-the-us...
Edit: Just to be clear before I'm downvoted into oblivion, I agree that the police and justice system are heavily biased against black people, I'm just not sure that sentence is true.