Mahmoud A. ElSohly, PhD, Research Professor at the Research Institute of Pharmaceutical Sciences at the University of Mississippi, wrote in a 2004 article "Potency Trends of Delta-9-THC and Other Cannabinoids in Confiscated Marijuana from 1980-1997," published in the Journal of Forensic Sciences:
"The potency (concentration of D9-THC) of marijuana samples rose from less than 1.5% in 1980 to approximately 3.3% in 1983 and 1984, then fluctuated around 3% till 1992. Since 1992, the potency of confiscated marijuana samples has continuously risen, going from 3.1% in 1992 to 4.2% in 1997. The average concentration of D9-THC in all cannabis samples showed a gradual rise from 3% in 1991 to 4.47% in 1997.
Hashish and hash oil, on the other hand, showed no specific potency trends. Other major cannabinoids [cannabidiol (CBD), cannabinol (CBN), and cannabichromene (CBC)] showed no significant change in their concentration over the years."
Is Today's Marijuana Significantly More Potent than Past Marijuana, and if so, Does That Make It More Dangerous to Patients?
The Journal of the American Medical Association in May 2004 published an article "Prevalence of Marijuana Use Disorders in the United States: 1991-1992 and 2001-2002," by Wilson M. Compton, MD, et al., in which the authors wrote:
"Among the adult U.S. population, the prevalence of marijuana use remained stable at about 4.0% over the past decade. In contrast, the prevalence of DSM-IV [psychological classifications of disorders] marijuana abuse or dependence significantly increased between 1991-1992 and 2001-2002, with the greatest increases observed among young black men and women and young Hispanic men.
Further, marijuana use disorders among marijuana users significantly increased in the absence of increased frequency and quantity of marijuana use, suggesting that the concomitant increase in potency of delta-9-THC [one of the active ingredients in marijuana] may have contributed to the rising rates.
[...] Increasing rates of marijuana use
disorders among marijuana users in the absence of increased quantity
and frequency of use strengthens the argument that the increasing rates may be attributable, in part, to increased potency of marijuana."
Mahmoud A. ElSohly, PhD, Director of the Marijuana Project at the University of Mississippi, which is funded by the National Institute on Drug Abuse, told The Washington Post in a June 4, 2002 article:
"This [marijuana] is a drug that produces tolerance. The smoker has to increase the amount he uses, just like alcohol.
High-potency pot ups the ante, producing a higher tolerance more quickly; and such higher levels of THC, quickly pumped into the body, can be great enough to induce the drug's more negative effects."
Lester Grinspoon, MD, Professor Emeritus at Harvard University, was quoted in a June 4, 2002 article in The Washtington Post:
"The whole issue on potency is a red herring. The more potent the pot, the less you use.
Marijuana users smoke until they achieve symptom relief, and then stop, whether it took two hits or an entire joint. In this regard, today's higher-potency pot is no more 'dangerous' than the bunk weed of yesteryear."
The Drug Policy Forum of Texas published a June 2002 booklet called "Are Texans Being Denied Access to a Vital Medicine?":
"Much has been said about marijuana today being much more potent than in earlier years, most of it wild exaggeration. There has always been a wide spectrum of potency in different strains. The most potent earlier strains were much more potent than the average potency of strains today.
According to the Potency Monitoring Project, a federally-sponsored research program at the University of Mississippi, marijuana potency has risen somewhat, but is less than double what it was 17 years ago. In 1985, commercial grade marijuana averaged 3.71% THC; in 1998, it had climbed to 5.57%, and by 2000 had dropped to below 5%. Highgrade "sinsemilla" marijuana (seedless) averaged 7.28% in 1985, climbing to an average 12.32% in 1998."
National Institute on Drug Abuse (NIDA)is cited in a June 4, 2002 article in The Washington Post:
"NIDA [National Institute on Drug Abuse] data from an ongoing project called Monitoring The Future supports the notion that smokers aren't getting higher from more potent joints.
Surveys show that joint sizes have dropped over the years from half a gram to about a quarter of a gram because more experienced smokers know that a smaller amount of pot can go a longer way toward making the smoker high."