Cannabis potency in North-East Italy: A ten-year study (2010–2019)

This paper presents data about potency of herbal and resin cannabis products seized during 2010–2019 in north-east Italy. More than 12,000 cannabis samples were analyzed and concentrations of THC, CBD and CBN were collected. The results of our study provided clear evidence for an increase in the potency of cannabis products across the study period, which is consistent with other studies. Globally, the median THC concentrations increased from about 6%–11%, but differences were found between herbal and resin materials. THC potency in resin materials increased more consistently across the study period with a dramatic raise during 2018–2019, with median THC contents around 17%. CBD concentrations were found to decrease constantly over the study period, especially in herbal materials, which had a mean CBD concentration of 0.3%. In particular, about 75% of the analyzed herbal samples had a CBD concentration which was less than 3% of the corresponding THC concentration. In contrast, more than 50% of the analyzed resin materials had a CBD concentration which was about 30% of the corresponding THC concentration. This is consistent with the increase in prevalence of high-potency seedless female herbal products observed in the same period and indicates that herbal and resin materials were produced from different varieties of cannabis plants. However, resin materials derived from high THC/low CBD cannabis plants were recently found. Different routes (e.g. northern Europe) or different modalities of distribution were assumed for these products. CBN concentrations were also considered and found to be very low and consistent across the study period indicating reliability of THC values used in statistical analysis. In conclusion, this study provided an accurate picture of cannabis products seized over a decade over a definite geographical area which can be extremely helpful for comparative purposes and for national and international statistical analyses on cannabis products