The use of illicit drugs in the U.S. has seen a two-year increase according to a National Survey, with marijuana becoming the drug of choice for young adults.

22.6 million Americans aged 12 and older used illicit drugs in 2010, resulting in an increase of drug use for the entire US population from 8.7 to 8.9 percent, the Substance Abuse and Mental Health Services Administration (SAMHSA) survey found.

Marijuana was the most popular drug among those used with 6.9 per cent of the population saying they have used the drug in 2010.

The survey suggests that the rise in marijuana use could be fueled by the legality of medical marijuana.

Gil Kerlikowske, director of the Office of National Drug Control Policy in the United States, said increases are especially prominent in states in which medical marijuana use is legal.

Emerging research reveals potential links between state laws permitting access to smoked medical marijuana and higher rates of marijuana use, Kerlikowske said in a statement, Reuters reported.

21 per cent of young adults aged between 18-25 were found to have taken illicit drugs in 2010, increasing from 19.6 in 2008.

Meanwhile, the use of methamphetamines has decreased almost by half between 2006-2010. The number of people aged 12 and older who used meth dropping to 353,000 last years, down from 731,000 in 2006.

Cocaine use also fell, dropping to 1.5 million users in 2010, from 2.4 million in 2006, the survey found.

We need to take what we are learning about helping people reduce their alcohol and tobacco use and figure out how to apply that to these other drugs in our society, said Peter J. Delany, director of SAMHSA's Office of Applied Studies. . We need to intervene before they need treatment or go to jail.

The report, released Sept 8, includes the results of the latest government survey on drug abuse, which involved about 67,500 people from around the country.

These statistics represent real lives that are at risk from the harmful and sometimes devastating effects of illicit drug use. This nation cannot afford to risk losing more individuals, families and communities to illicit drugs or from other types of substance abuse -- instead, we must do everything we can to effectively promote prevention, treatment and recovery programs across our country, said SAMHSA administrator Pamela S. Hyde.