Press Release

Today's marijuana is twice as strong as it was in the mid-1980's. The study, sponsored by the National Institute on Drug Abuse, found that the average levels of the active ingredient in marijuana, THC, jumped from 3.5% in 1985 to over 7% in 2003.

These results are based on the University of Mississippi's Marijuana Potency Project analyses of over thirty thousand marijuana seizure samples over the 18-year period. These drug seizures are from federal law enforcement operations at our borders and within the country. The Drug Enforcement Administration forwards these marijuana samples from its eight forensic laboratories around the country to the University of Mississippi's potency lab.

Domestic eradication samples are also analyzed separately. In 2003, only 598 of the 2,325 samples analyzed were from domestic marijuana eradication. Compare this with over 34,000 cultivated marijuana plots eradicated through DEA's Domestic Cannabis Eradication and Suppression Program indicates that the University of Mississippi eradication sample is quite small. Over the 1985 to 2003 time period, potency of the analyzed eradication samples rose from 2% to 4%.

The seizure samples consist of three types of cannabis: low-potency ditchweed, marijuana, and high-potency sinsemilla. The majority of the 2003 seizures were marijuana, with an average potency of nearly 6%. Twenty-percent of the samples were sinsemilla, which had an average potency of over 14%. The distribution of these cannabis-types is shown in figure 1.

The physical description of the seized marijuana includes high-potency buds, marijuana leaf, and kilobricks. The buds have risen in potency from below 6% in 1985 to 10% in 2003. Potencies of the marijuana leaf and kilobricks have risen from 3% to 5%. The distribution of these physical descriptions is shown in figure 1.

Analyses to-date on twenty marijuana seizures in 2004 shows a potency exceeding 9%, and has been as high as 27% from a sample seized in the Northwest.

The increasing strength of today's marijuana may be linked to increasing mentions of marijuana in hospital emergency rooms. The Drug Abuse Warning Network (DAWN) is a national surveillance system that monitors trends in drug-related emergency department visits and deaths, and is operated by the Substance Abuse and Mental Health Services Administration (SAMHSA), of the U.S. Department of Health and Human Services. DAWN emergency room mentions of marijuana have increased nationally from twenty thousand in the late 80's to nearly 120,000 in 2002 (see figure 2 below).

In a city such as San Diego, marijuana emergency room mentions now exceed mentions of any other illicit drug (1,174 marijuana mentions in 2002, compared to 807 cocaine mentions).

Marijuana is increasingly the primary substance of abuse for drug treatment admissions. According to the Treatment Episode Data Set (TEDS), in 2002 15% of TEDS drug treatment admissions were for marijuana compared to 6% in 1992. Higher potency marijuana may be a factor in this trend.

Figure 1: Distribution of the 2003 cannabis seizure samples analyzed by the University of Mississippi.

Figure 2: Comparison of Cannabis Potency Trends with Dawn Emergency Room Mentions of Marijuana.