Americans take 80 percent of all prescription painkillers taken in the world. i have also read that americans take about 80% of psycotic drugs in the world. are americans weak? hypochondriacs? http://news.yahoo.com/video/world-22186928/drug-czar-warns-about-prescription-painkillers-24976759
They're wealthy and bored; materialism, their strong suit, is not sufficiently satisfying or comforting. Edit: to add, materialism (above the fundamentals needed) appears to undermine happiness in some ways.
If non-Americans had to put up with 8 years of George W. Bush and 4 years of Obama they'd need pain killers too.
Take the average suburbia. You have houses, a safeway, a jamba juice a starbucks and a McDonalds. If you're lucky a few parks here and there. Does this sound like any fun? Americans have such a short attention span that they need drugs to make every little thing that much more exciting.