Potency trends of Δ9 -THC, cannabidiol and cannabinol in cannabis in the Netherlands: 2005-2015.

BACKGROUND AND AIMS:

Between 2000 and 2005 the average percentage of tetrahydrocannabinol (THC) in marijuana as sold in Dutch coffee shops has increased substantially, especially the potency of domestic products (Nederwiet and Nederhasj) increased. In contrast with imported marijuana Nederwiet hardly contained any cannabidiol (CBD), a cannabinoid that is thought to offset some of the adverse effects of THC. In 2005, the THC-content in Nederwiet was significantly lower than in 2004. This study investigates the further de- or increase of cannabinoidsin these cannabis products.

METHODS:

From 2005 until 2015 five different cannabis products were bought anonymously in 50 coffee shops that were randomly selected each year from all coffee shops in The Netherlands. 2126 cannabis samples were bought, consisting of 664 Nederwiet samples (most popular), 537 Nederwiet samples (supposed strongest varieties), 183 imported herbal cannabis samples, 140 samples of cannabis resin made of Nederwiet and 602 samples of imported cannabis resin. All samples were chemically analyzed for their THC, CBD and cannabinol (CBN) content.

RESULTS:

Between 2005 and 2015, the mean potencies of the most popular and the strongest Nederwiet and of imported cannabis resin were 16.0 ± 4.0%, 17.0 ± 4.0% and 16.5 ± 6.3% respectively. Imported herbal cannabis (6.5 ± 2.5%) and cannabis resin made from Nederwiet (30.2 ± 16.4%) contained respectively less (β = -10.0, p < 0.001) and more (β = 13.7, p < 0.001) THC than imported cannabis resin. Linear regression models were used to study the trends in THC of the different cannabis products over time. A marginal, but significant (p < 0.001), overall decline of THC per year of 0.22 percent was found in all cannabis products. However, no significant difference was found between the 5 products in the THC linear trajectories across time. Of all the cannabis products, only imported cannabis resin contained a relatively high CBD/THC ratio (median 0.42).

CONCLUSION:

The average tetrahydrocannabinol (THC) content of the most popular herbal cannabis products in The Netherlands has decreased slightly since 2005. The popular Nederwiet type still has a relatively high THC to cannabidiol ratio. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.