Medical marijuana is being used to relieve pain by people of all ages and backgrounds -- including the elderly, Baby Boomers and 20- to 30-somethings, according to new data from the Arizona Department of Health Services.

Arizonans voted in November 2010 to allow cancer patients and others with certain debilitating illnesses to get a medical-marijuana card with a doctor's approval. Since marijuana was legalized for medicinal use, more than 22,200 people have received permission to smoke, eat or otherwise ingest it to ease their ailments.

Of those, nearly three-quarters are men, and nearly 85 percent of all patients have requested to grow their own cannabis. Officials denied nine applications.

People ages 31 to 50 make up the largest group of patients using the drug to counter illness, representing 40 percent of all medical-marijuana users. Those 51 to 81 account for more than 35 percent of patients, while 18- to 30-year-olds make up about 25 percent. People younger than 18 represent less than 1 percent.

The overwhelming majority of medical-pot users reported chronic pain as their medical condition, while muscle spasms were also high on the list, health officials reported. Other ailments include hepatitis C, cancer and seizures.

Geographically, medical-cannabis users mostly live in metro Phoenix and other highly populated areas, including metro Tucson, Yavapai County, Kingman and Lake Havasu City. Just six areas throughout the state have no medical-pot users, the data showed, and all are on Native American reservations.

Will Humble, director of the state's Department of Health Services, said the data indicate the state has avoided becoming a "largely recreational program as opposed to medical."

"The fact that we've got an older demographic tends to make me think that we did a decent job," Humble said. "When you add up the folks older than 41, it's well over half of the participants. That doesn't mean there's not recreational users in that group, but as you get older, you do tend to get more debilitating medical conditions, so I'm encouraged by that."

Opponents of medical pot, however, are discouraged by the data. Carolyn Short, chairwoman of Keep Arizona Drug Free, campaigned against efforts to legalize medical pot and said the data suggests most patients are faking or exaggerating their problems. She believes Arizona's data indicates that nearly all patients are substance abusers, based on research by an addiction psychiatrist who opposed the legalization of medical marijuana in 2010.

"Do I think there are people who aren't sick who are on that list?" she asked. "Absolutely. I think that people ought to listen to their doctors instead of their drug dealers."

Short said marijuana should be used only if a person has a terminal condition and doctors have exhausted all treatment and believe it is necessary. "I don't have a problem with that," she said.