We all know Americans pop prescription drugs like M&Ms, but for what, exactly? According to a new infographic from GOOD and Stanford Kay, we're worrying ourselves sick -- and right into the hands of Big Pharma.

The chart details last year's 10 most prescribed psych drugs, and it reads like the medicine cabinet of Liza Minnelli. Nine out of 10 drugs deal in anxiety, with Xanax, Lexapro, and Ativan leading the pack. Seven treat depression. And nearly all can be taken for multiple disorders.

The numbers here are staggering. Doctors wrote 44 million prescriptions for Xanax and 27.7 million for Lexapro. Valium, the least popular on the list, was prescribed 14 million times. Which makes you wonder: Are we really so worked up? So sad? Or is something else to blame?

In 2009, the pharmaceutical industry spent $4.5 billion -- the budget of a small country -- marketing this stuff (a drop in the bucket, really, when you consider that Americans spend $200 billion a year on prescription meds). The chart doesn't make the direct connection, but it stands to reason that the crap we put in our bodies has everything to do with these ad dollars. Cymbalta launched into the list of top-10 psychiatric drugs last year, after being 16th in 2008. We'd be surprised if its TV spots, which air, oh, every other second, don't have something to do with it.

Here's the most, um, depressing part: When you tally up all the prescriptions doctors wrote, the figure actually outnumbers the U.S. population. So yeah, we're over-medicated. Something else to feel anxious about.