Depressed and anxious, more and more Americans over 50 are abusing drugs and alcohol — and the trend doesn't show signs of slowing.

The number of older adults reporting recent illegal drug use nearly doubled between 2002 and 2007, according to a recent report from the Substance Abuse and Mental Health Services Administration. The percentage of older adults checking into drug rehab nearly doubled between 1992 and 2008. By 2020, the United States Department of Health estimates the need for substance abuse treatment among Americans over age 50 will double again.

Depression and anxiety are the No. 1 reason older adults abuse drugs or alcohol, according to a survey from Caron Treatment Centers, a national nonprofit substance abuse treatment provider. Financial struggles and the stresses of retirement also contribute to substance abuse.

Oxycontin is the most abused prescription drug among older adults, according to The Miami Herald, but anxiety and anti-depressants are also frequently misused. About 20 to 25 percent of people are at risk of developing a dependency to prescription drugs.

For the survey, Caron Treatment Centers surveyed adults who sought treatment for drug or alcohol addictions. The majority of those surveyed said they first tried drugs or alcohol before the age of 25, but 40 percent said they didn't consider themselves to be abusers until after age 48.

"Older adults face a distinct set of challenges as they enter their golden years," said Dr. Barbara Krantz, medical director of the Hanley Center, a drug and alcohol treatment and recovery center acquired by Caron Treatment Centers. "This transitional period of life is unique and leads to difficulty in dealing with stressful situations, such as an early retirement or financial strains, which in turn may lead to serious anxiety and depression. Without the proper tools to manage their emotions, older adults turn to quick fixes such as alcohol and drugs, creating the perfect storm for dependency."

Few drug treatment centers are equipped to deal with the rise in substance abuse among older adults, but more and more programs targeting seniors are popping up across the country.

"This is a different population with different needs," Ravi Chandiramani, corporate medical director for Journey Healing Centers, a substance abuse treatment center with facilities in Utah and Arizona, told the Deseret News. "We're rethinking a lot of the way we do things."