Taking a pill to feel normal, even a pill sanctioned by the medical profession, led to a strange situation: it made people wonder what “normal” really was. What does it mean when people feel more like themselves with the drug than without it? Does the notion of “feeling like themselves” lose its meaning if they need a drug to get them there?…

Nearly 50 years after Valium was introduced and aggressively marketed, we’ve learned its lessons well. My generation of aging baby boomers does its brain styling, by and large, with antidepressants: Prozac, Wellbutrin, Celexa, Paxil, Zoloft. And for my daughters’ generation, the millennials, the pills of choice tend to be Ritalin and Adderall, for mental focus.

But when Americans are feeling out of sorts, we are still more likely to turn to anti-anxiety drugs than to any other kind. The leading successor to Valium, Xanax, outsells every other psychiatric drug on the market (48.7 million prescriptions last year). And even Valium is still out there, the classic little-black-dress of tranquilizers. In 2011, 14.7 million prescriptions were written for the drug that first made its cultural mark as a Rolling Stones song (“Mother’s Little Helper”) back in 1966.