A very interesting series of articles by Columbia Law Professor Tim Wu about zones in the American legal system where laws are not enforced... Where otherwise illegal activities are legal. There are multiple sections, but I'm linking the second, which is about drug use:

The current program of drug legalization in the United States is closely and explicitly tied to the strange economics of the U.S. health-care industry. The consequence is that how people get their dopamine or other brain chemicals is ever more explicitly, like the rest of medicine, tied to questions of class.

Antidepressants and anxiety treatments aren't cheap: A fancy drug like Wellbutrin can cost anywhere from $1,000 to $2,400 a year. These drugs also require access to a sympathetic doctor who will issue a prescription. That's why, generally speaking, the new legalization program is for better-off Americans. As the National Center on Addiction and Substance Abuse at Columbia University reports, rich people tend to abuse prescription drugs, while poorer Americans tend to self-medicate with old-fashioned illegal drugs or just get drunk.

The image painted here is of a society whose psychology is largely chemically modified, and has been largely chemically modified for a long time. Wherein low tech drugs like cocaine and cigarettes, which are taken regularly in small doses in other societies, have been replaced with high tech drugs that have the exact same effects in both low and high doses, but which are also extremely expensive due to patents.

I'd argue that the act of getting high for the thrill of it is far more innocent than maintaining a regular drug regiment in order to feel normal... to feel happy about one's life. Now, there is such a thing as mental illness... some people really do need drugs in order to "feel normal." But one wonders how much of our health care budget goes to substance abusers maintaining addictions... putting an artificial sheen on life. There is no way to systematically tell the difference.

American lawbreaking: How laws die. - By Tim Wu - Slate Magazine