I've posted about the prescription drug overdose epidemic before. It followed a major shift in physician prescribing patterns beginning in 1999 when physicians came under increased pressure to treat pain more aggressively with narcotics. This was driven by consumer demand, initiatives by agencies such as Joint Commission and indoctrination of providers through various “educational” efforts.
Here is an article examining the trend in more detail, with state-by-state data. Free full text via Medscape.