Needle in a haystack, or behind a white picket fence?

For once, I appreciate the overcast Boston day that's unfolding outside my window. It's the appropriate setting for an article I stumbled upon today, both gray and depressing.

The story focuses on the sharp increase in heroin usage among middle and upper class kids, its pervasiveness, and (obvious) detrimental effects. The author clearly did his research, as I had heard about most of the drugs he mentioned--at parties, in university hallways, among friends even. So he would have had to really 'get in there' to get the facts.
However, what I would have liked to see is a comparison between usage among kids from different layers of society. Heroin is apparently pretty cheap now, as he points out in the article, which renders it accessible to people from most of the income-spectrum. Some contrast might provide a link to understanding its widespread use. The problem with the argument presented is that it's lacking; all we know is that apart from the sheer enjoyment of the euphoric high, the interviewees were inadvertently pushed to it by societal pressures to excel and succeed. I feel there might be more to it.