So you are saying that there are social circumstances that will raise the rate of consumption, but that raising the rate of consumption doesn't in fact raise the rate of addiction. In other words, if 50 per cent of the troops in Vietnam had been using crack, this would not have affected the rate at which, on returning to the U.S., they became addicted. They would have kicked the habit on reaching home. That's the idea. Drug consumption can go up in a particular population, fueled by stress, but the rate of addiction doesn't go up no matter what the degree of stress.
Most people can walk away from high drug use if their lives become more normal.
Of course, the stress of the ghetto isn't the only situation that fuels high drug consumption. Plenty of affluent people who for some reason or another do not find their lives rewarding also escape into drugs. That is an interesting question and one that can't satisfactorily be answered until much more research is done. There are conundrums. Again, it is estimated that 21 million people tried cocaine in 1988.