California
Voters in the state of California approved a “medical” marijuana act in 1996 and the law went into effect the following day. There are an estimated 300,000 to 400,000 “medical” marijuana “patients” in California. In cities like San Diego where the issue has been closely examined, only 2% of those smoking marijuana under the guise of medicine have serious conditions such as AIDS, glaucoma and cancer. A full 98% are “treating” more minor conditions such as back and neck pain, anxiety, muscle spasms, insomnia, headaches and other insignificant conditions. But even more troubling is that 12% of the users are under 21!
Source: California Police Chiefs Association. Medical Marijuana Dispensary Information, Medical Marijuana Dispensaries-San Diego (Power Point).  http://www.californiapolicechiefs.org/nav_files/medical_marijuana.html
Source: CNN Money.com How marijuana became legal by Roger Parloff. September 18, 2009

Oregon
Voters in the state of Oregon approved a “medical” marijuana act in 1998.  As of July 1, 2010, the Oregon Medical Marijuana Program has 36,380 individuals that legally hold “medical” marijuana ID cards, and of those, 89.6% are treating “severe pain” (an indefinable term that is being used to cover medical conditions such as menstrual cramps, headaches, and minor arthritis) rather than the more serious conditions such as cancer (3.9%), glaucoma (1.5%) and HIV+/AIDS (1.6%). 
Source: Oregon.gov, Oregon Medical Marijuana Program (OMMP) http://oregon.gov/DHS/ph/ommp/index.shtml

I'll let the numbers speak for themselves. For the record, I also feel less stress and my aches and pains go away with a little Scotch.