WASHINGTON — The generation that once celebrated sex, drugs and rock 'n' roll as a rite of passage is carrying substance abuse into retirement, says a U.S. government survey released Thursday.

Illicit drug use shot up 116 percent over the past five years for Americans between the ages of 55 and 59, according to a 2007 study

by the U.S. Substance Abuse and Mental Health Services Administration.

In that age group, 4.1 percent of those queried said they had used illicit drugs within the previous month, up from 1.9 percent in 2002.

Similarly, 5.7 percent of those between the ages of 50 and 54 reported using illicit drugs, up from 3.4 percent in 2002, a 68 percent increase.

"This is the baby boomer generation," said John Walters, director of the White House Office of National Drug Control Policy.

Millions of boomers who developed a dependency on marijuana, cocaine, heroin, hallucinogens or other drugs as teenagers, he said, are now living with the disease of substance addiction.

"We are carrying the illness into the age group for the rest of our lives," he said.

Throughout much of the 1960s, use of alcohol and illicit drugs was regarded as an accepted — if illegal — expression of youthful rebellion, said Walters.

"Everybody looked the other way," he said, instead of spotting red flags for substance abuse.

"It was so accepted — the sex, drugs and rock 'n' roll — and it's caught up with a lot of us — if we're still alive," said Candy Finnigan, 61, who works to help people kick substance-abuse problems and has appeared in the A&E network's docudrama "Intervention."

Despite the development of clinics that specialize in helping older addicts recover, substance abusers often find themselves without the support of close family and friends that is available to teen abusers, Finnigan said.

That's one reason why millions go untreated.

A total of 23.2 million Americans needed treatment last year for drug or alcohol abuse, and only 2.4 million got it, said SAMHSA's acting administrator, Eric Broderick.

Of the remaining 20.8 million who needed treatment and didn't get it, 94 percent said they did not feel they needed help, said Broderick.

In its 2007 National Survey on Drug Use and Health, SAMHSA queried about 68,000 Americans over 12, a sample that allows researchers to represent the nation at large.

Among youths between the ages of 12 and 17, illicit drug use fell significantly between 2002 and 2007, the study found.

In that age group, 9.5 percent of the youths said they had used marijuana or other illicit drugs in the previous month, down from 11.6 percent in 2002 and 9.8 percent in 2006.

That, said Broderick, is cause for comfort. The earlier people start using illicit drugs, the greater is the risk of abuse, he said, in part because judgment and other brain functions are still developing through the teen years.

"When people use early, use young and use much, they do so for the rest of their lives," Broderick said.

Walters said part of the reason for this age group's decline in use has been a government campaign warning young Americans of the dangers of substance abuse and to urge parents, teachers, doctors and others in a teenager's support community to intervene when trouble signs emerge.

"When we push hard, we make progress," said Walters. "When we help to educate and to protect, we save lives."

Marijuana remains the most commonly used illicit drug for teenagers, 5.8 percent of whom reported using the drug in 2007, down from 6.0 percent the year before.

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