This goodie from the Neuroskeptic blog-
Antidepressant sales are rising in most Western countries, and they have been for at least a decade. Recently, we learned that the proportion of Americans taking antidepressants in any given year nearly doubled from 1996 to 2005.
The authors examined medical records from 1.7 million British patients in primary care (General Practice, i.e. family doctors.) They found that antidepressant sales rose strongly between 1993 and 2005, not because more people are taking these drugs, but entirely because of an increase in the duration of treatment amongst the antidepressant users. It's not that more people are taking them, it's that people are taking them for longer.
In fact, the number of people being diagnosed with depression and prescribed antidepressants has actually fallen over time. The rate of diagnosed depression remained steady from 1993 to about 2001, and then fell markedly, by about a third, up to 2005. This trend was seen in both men and women, but there were age differences. In 18-30 year olds, there was a gradual increase in diagnoses before the decrease. (Note that these graphs show the number of people getting their first ever diagnosis of depression in each year.)
More here. Worth a read. (Sorry for the colors and what not, blogger is acting up again!)