When you think of people who use illegal drugs, you think first of young adults, like the hippies and flower children of the 60s. But those hippies have gray hair now, and increasingly it's Grandpa who's getting high.

A new study done for the Substance Abuse and Mental Health Services Administration shows a dramatic increase in illicit drug use among people over 50. Researchers say baby boomers who discovered marijuana, cocaine and other drugs as young people apparently haven't given it up.

This isn't just a matter of concern for law enforcement, researchers say. With a portioin of the aging population have used their drugs over a lifetime, it could double the need for substance abuse treatment services by 2020.

"This new data has profound implications for the health and well-being of older adults who continue to abuse substances," said SAMHSA Administrator, Pamela S. Hyde, J.D. "These findings highlight the need for prevention programs for all ages as well as to establish improved screening and appropriate referral to treatment as part of routine health care services."

Substance abuse at any age is associated with numerous health and social problems, but age-related physiological and social changes make older adults more vulnerable to the harmful effect of illicit drugs use.

"This study highlights the fact that older Americans face a wide spectrum of healthcare concerns that must be addressed in a comprehensive way," said Assistant Secretary for Aging, Kathy Greenlee. "The Administration on Aging is committed to working with SAMHSA and all other public health partners in meeting these challenges."

The latest SAMHSA short report, Illicit Drug Use Among Older Adults, shows that an estimated 4.3 million adults aged 50 or older (4.7 percent) used an illicit drug in the past year. In fact, 8.5 percent of men aged 50 to 54 had used marijuana in the past year, as opposed to only 3.9 percent of women in this age group.

The SAMHSA report also shows that marijuana use was more common than nonmedical use of prescription drugs among males 50 and older, but among females the rates of marijuana use and nonmedical use of prescription drugs were similar.

Although marijuana use was more common than nonmedical use of prescription drugs for adults age 50 to 59, among those aged 65 and older, nonmedical use of prescription drugs was more common than marijuana.

The report, which examines the prevalence of any illicit drug use, marijuana use, and nonmedical use of prescription drugs, is based on data collected during 2006 to 2008 from a nationally representative sample of 19, 921 adults aged 50 or older who participated in SAMHSA's National Survey on Drug Use and Health.

If you think a friend or loved one is abusing cocaine, better read this.