An investigation of procedures reported to increase potency of marijuana: a chemical analysis and psychological interpretation

Int J Addict. 1978 Jul;13(5):831-7. doi: 10.3109/10826087809039306.


Three basic procedures from the "underground press" for increasing the potency of marijuana were tested quantitatively: Black Merta, Dry Ice, and isopropanol--water extraction. In all methods there was not significant change in THC, CBN, or CBD content before and after treatment. The persistence of procedures which have no measurable effect on the chemical properties of the drug is presented as additional evidence for the importance of psychological factors in perceived drug effects.

MeSH terms

  • Cannabidiol / analysis
  • Cannabinol / analysis
  • Cannabis
  • Cognitive Dissonance
  • Dronabinol / analysis
  • Dronabinol / pharmacology*
  • Humans
  • Spectrophotometry
  • Substance-Related Disorders / psychology*


  • Cannabidiol
  • Dronabinol
  • Cannabinol