New trends in cannabis potency in USA and Europe during the last decade (2008–2017)

  • Suman Chandra
  • Mohamed M. Radwan
  • Chandrani G. Majumdar
  • James C. Church
  • Tom P. Freeman
  • Mahmoud A. ElSohlyEmail author
Original Paper


Through the potency monitoring program at the University of Mississippi supported by National Institute on Drug Abuse (NIDA), a total of 18108 samples of cannabis preparations have been analyzed over the last decade, using a validated GC/FID method. The samples are classified as sinsemilla, marijuana, ditchweed, hashish, and hash oil (now referred to as cannabis concentrate). The number of samples received over the last 5 years has decreased dramatically due to the legalization of marijuana either for medical or for recreational purposes in many US states. The results showed that the mean Δ9-THC concentration has increased dramatically over the last 10 years, from 8.9% in 2008 to 17.1% in 2017. The mean Δ9-THC:CBD ratio also rose substantially from 23 in 2008 to 104 in 2017. There was also marked increase in the proportion of hash oil samples (concentrates) seized (0.5–4.7%) and their mean Δ9-THC concentration (6.7–55.7%) from 2008 to 2017. Other potency monitoring programs are also present in several European countries such as The Netherlands, United Kingdom, France, and Italy. These programs have also documented increases in Δ9-THC concentrations and Δ9-THC:CBD ratios in cannabis. These trends in the last decade suggest that cannabis is becoming an increasingly harmful product in the USA and Europe.


Cannabis Potency monitoring Sinsemilla Marijunna Hashish Hash oil Concentrates Δ9-THC CBD CBN CBG 



This work is supported in part by the National Institute on Drug Abuse (contract # N01DA-15-7793). Tom Freeman is funded by a senior academic fellowship from the Society for the Study of Addiction.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.National Center for Natural Products Research, School of PharmacyUniversity of MississippiUniversityUSA
  2. 2.Department of Computer Science (JCC)University of West GeorgiaCarrolltonUSA
  3. 3.Addiction and Mental Health Group (AIM), Department of PsychologyUniversity of BathBathUK
  4. 4.Institute of Psychiatry, Psychology and NeuroscienceKing’s College LondonLondonUK
  5. 5.Department Pharmaceutics and Drug Delivery, School of PharmacyUniversity of MississippiUniversityUSA

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