Variability of cannabis potency in the Venice area (Italy): A survey over the period 2010–2012

Abstract

Cannabis is the most widely used illicit substance globally, with an estimated annual prevalence in 2010 of 2.6-5.0% of the adult population. Concerns have been expressed about increases in the potency of cannabis products. A high tetrahydrocannabinol (THC) content can increase anxiety, depression, and psychotic symptoms, and can increase the risk of dependence and adverse effects on the respiratory and cardiovascular systems in regular users. The aim of this study was to report statistical data about the potency of cannabis products seized in the north-east of Italy, in a geographical area centred in Venice and extending for more than 10,000 km(2) with a population of more than two million, by investigating the variability observed in THC levels of about 4000 samples of cannabis products analyzed over the period 2010-2012. Overall median THC content showed an increasing trend over the study period from about 6.0% to 8.1% (6.2-8.9% for cannabis resin, 5.1-7.6% for herbal cannabis). The variation in the THC content of individual samples was very large, ranging from 0.3% to 31% for cannabis resin and from 0.1 to 19% for herbal cannabis. Median CBN:THC ratios showed a slightly decreasing trend over the study period, from 0.09 (2010) to 0.03 (2012), suggesting an increasing freshness of submitted materials. Median CBD:THC ratios also showed a decreasing trend over the study from about 0.52 (2010) to 0.18 (2012), likely due to the increase in submissions of materials from indoor and domestic cultivation with improved breeding methods.

Potency trends of Δ9‐tetrahydrocannabinol, cannabidiol and cannabinol in cannabis in the Netherlands: 2005–15

“…The average THC percentage of more than 15% is relatively high compared with studies performed in other countries [19][20][21]. Partly, this might be because we analysed samples purchased at the retail level.…”

Increasing potency and price of cannabis in Europe, 2006–16

“…The effects of these changes appear to be evident in the French cannabis market, as documented by a 25-year study of police seizures [23]. Increases in THC concentrations were also detected in resin samples collected from police seizures in the United Kingdom from 2004-05 [18] to 2015-16 [24] and in Italy from 2010 to 2013 [25,26]. Increases in THC concentrations were also detected in resin samples collected from police seizures in the United Kingdom from 2004-05 [18] to 2015-16 [24] and in Italy from 2010 to 2013 [25,26].…”

Cannabis potency in the Venice area (Italy): Update 2013

“…Geographical features of the study area and analytical procedures used to investigate cannabinoids contents of submitted materials were previously reported in detail. [1] A specific classification of cannabis products have been carried out to overcome the impossibility of discerning between sinsemilla products and others herbal loose materials, which was a limitation of the previous work. However, undifferentiated data have also been reported to make current data comparable with the previous ones.…”

“…In a previous paper, [1] data about cannabis potency of about 4000 samples of cannabis products seized over the period 2010-2012 in the Venice area (Italy) showed an overall increasing trend of the median delta-9-tetrahydrocannabinol (THC) content over the study period from about 6.0% to 8.1%, ranging from 6.2% to 8.9% for cannabis resin and from 5.1% to 7.6% for herbal cannabis. Median CBD:THC (CBD, Cannabidiol) ratios showed a significant decreasing trend over the study period from about 0.52 in 2010 to 0.18 in 2012.…”