In 2000, more than half a million people over the age of 55 in the US had used illicit drugs in the last month. Opiates, second only to alcohol, account for 14 percent of all drug treatment admissions over age 55. Heroin is the drug of choice for nine out of 10 opioid abusers.

Physical decline, loss of friends or loved ones, and decreasing independence can contribute to late-onset addiction -- but the startling phenomenon in older adult heroin use is the existence of the lifetime user.

Seniors may be predisposed to illegal drug use because of past use and reinforcing factors, such as chronic or acute pain management, explained Donna White, a registered nurse at Lemuel Shattuck Hospital in Massachusetts, in a presentation at the June Aging with Dignity Conference in Worcester, Mass. At White's hospital, approximately 25 percent of patients over the age of 50, who were referred to addiction services, abused heroin.

According to the Office of National Drug Control Policy, "The majority of clients entering treatment for heroin abuse are older, Caucasian males who have received drug treatment previously."

Because the kidneys and liver do not process heroin as rapidly as the body ages, older, longtime users are able to taper their use of the drug and avoid overdose, explained White. However, the rising purity of street heroin makes health risks even greater than they would be for this already vulnerable population.

Research and services are limited for this specific population of older adults, despite its special needs. Although 24 percent of all outpatient methadone clients are 45 or older, according to 1996 survey data, there are few, if any, methadone treatment programs that gear their services specifically to older adults.

Population projections predict that, by 2020, the percentage of people age 50 and older needing treatment for illicit drug use will be five times higher than it is today. The number of substance abuse treatment admissions age 55 or older has increased already, according to SAMHSA.

"Many [baby boomers] are expected to continue their alcohol and other drug dependency through their later years... presenting a significant challenge to the public health system," White said.