A 2008 survey by the Substance Abuse and Mental Health Services Administration found the rate of illicit drug use holding steady, but noted a decline in prescription drug misuse and methamphetamine use.

According to SAMHSA's 2008 National Survey on Drug Use and Health, the overall rate of past-month illicit drug use — including marijuana/hashish, cocaine (including crack), heroin, hallucinogens, inhalants and prescription drug misuse — among Americans age 12 and older held steady at 8 percent between 2007 and 2008.

However, misuse of prescription drugs declined over that same period, from 2.8 percent to 2.5 percent, while methamphetamine use plummeted by more than half between 2006 and 2008, from 731,000 to 314,000 users.

Although past-month illicit drug use among 12- to 17-year-olds also stayed the same between 2007 and 2008, the rate has declined significantly since 2002, from 11.6 percent to 9.3 percent.

Past-month alcohol use, as well as binge and heavy drinking rates, decreased between 2007 and 2008. Among underage people (ages 12 to 20), past-month drinking went from 28.8 percent to 26.4 percent.

Similarly, the past-month cigarette use rate among Americans age 12 and older went unchanged between 2007 and 2008, but between 2002 and 2008 the rate has gone from 26 percent to 23.9 percent.

Among 12- to 17-year-olds, the rate declined from 9.8 percent in 2007 to 9.1 percent in 2008. In 2002, the rate was 13 percent.

"The results of this survey underscore the progress made and challenges we face," SAMHSA Acting Administrator Eric Broderick said in a press release. "While we have made progress on many fronts, declines in marijuana use among youth have stalled out, and the rates of illicit drug use among young adults [age 18 to 25] have not budged for years."

The survey also found that in 2008 approximately 22 million Americans age 12 and older met the diagnosis criteria for substance dependence or abuse. That number has remained the same since 2002.

Furthermore, more than 23 million Americans ages 12 and older needed treatment, such as hospital inpatient care, for a drug or alcohol use problem, but just 2.3 million received treatment.