U.S. Has Highest Levels of Illegal Drug Use

In spite of the most stringent drug policies and punitive laws in the world, the United States also has the highest levels of lifetime illegal cocaine and marijuana use, according to a study of more than 54,000 people in 17 countries.

The United States also has the highest rate of lifetime tobacco use but comes in third in alcohol use, behind the Ukraine and Germany. The study, by Louisa Degenhardt of the University of New South Wales (Sydney, Australia) and colleagues, is based on the World Health Organization's Composite International Diagnostic Interview (CIDI).

The survey, which asked participants about their lifetime cocaine, marijuana, tobacco and alcohol use, found that 16.2% of people in the United States have used cocaine at some point during their lives. This rate was almost four times the rate of the second-place country, New Zealand, where 4.3% said they had tried cocaine.

The researchers also found that 42.4% of people in the United States reported marijuana use during their lifetime. New Zealand was second with 41.9%, but the two countries were far ahead of the other 15 in lifetime marijuana use.

This trend has also been reported in the National Survey on Drug Use and Health (NSDUH) conducted annually by Substance Abuse and Mental Health Services Administration (SAMHSA). In 2013, that survey indicated that an estimated 24.6 million Americans aged 12 or older—9.4 percent of the population—had used an illicit drug in the past month.

The number of current illicit drug users (those who have used in the past month) is up from 8.3 percent in 2002. The increase is mainly due to an increase in the use of marijuana.

While the use of other illegal drugs has leveled off or declined over the past decade, NSDUH figures show that past-month marijuana users increased from 5.8 percent to 7.5 percent from 2007 to 2013.

"Drug use is related to income, but does not appear to be simply related to drug policy, since countries with more stringent policies towards illegal drug use did not have lower levels of such drug use than countries with more liberal policies," Degenhardt and her colleagues write.

"The United States, which has been driving much of the world's drug research and drug policy agenda, stands out with higher levels of use of alcohol, cocaine and cannabis, despite punitive illegal drug policies, as well as (in many U.S. states) a higher minimum legal alcohol drinking age than many comparable developed countries," the authors report.

"The Netherlands, with a less criminally punitive approach to cannabis use than the United States, has experienced lower levels of use, particularly among younger adults," the report says. "Clearly, by itself, a punitive policy towards possession and use accounts for limited variation in nation-level rates of illegal drug use."

Here are some of the other key findings of the study:

• Males were more likely to have used all drug types, but that gender gap is closing among the youngest participants.
• Younger adults were more likely to have used all the drugs in the study than the older adults.
• Those who were never married or previously married had higher rates of tobacco, cocaine and marijuana use, but not alcohol use.
• Higher income was associated with higher rates of both illegal and legal drug use.
• Tobacco use is more prevalent among people who have been previously married but less likely among those never married.
• Alcohol use by age 15 was much more common among Europeans than in the Middle East or Africa.

"There was greater drug involvement among younger than older adults in all countries, suggesting that drug use has and may continue to change over historical time," the authors write. "Interestingly, there was also evidence to suggest that male-female differences in risk of initiating drug use may be changing in more recent birth cohorts.

"This change was a consistent finding across countries, suggesting that a general shift may be occurring with respect to the traditional sex differences so often documented with drug use."

Degenhardt L, et al. (2008) "Toward a Global View of Alcohol, Tobacco, Cannabis, and Cocaine Use: Findings from the WHO World Mental Health Surveys." PLoS Medicine 1 July 2008