Strong increase in total delta-THC in cannabis preparations sold in Dutch coffee shops

Abstract

The total concentration of THC has been monitored in cannabis preparations sold in Dutch coffee shops since 1999. This annual monitoring was issued by the Ministry of Health after reports of increased potency. The level of the main psychoactive compound, Δ9-tetrahydrocannabinol (THC), is measured in marijuana and hashish. A comparison is made between imported and Dutch preparations, and between seasons. Samples of cannabis preparations from randomly selected coffee shops were analyzed using gas chromatography (GC-FID) for THC, CBD and CBN. In 2004, the average THC level of Dutch home-grown marijuana (Nederwiet) (20.4% THC) was significantly higher than that of imported marijuana (7.0% THC). ..