Cannabis resin – or “hash” – has increased in strength by nearly 25% over the past half century, a major international study has revealed.
Researchers with the Addiction and Mental Health Group at the University of Bath analysed data from more than 80,000 cannabis street samples tested in the past 50 years in the US, UK, Netherlands, France, Denmark, Italy and New Zealand.
In herbal cannabis, THC concentrations increased by 14% between 1970 and 2017. This was primarily due to a rising market share of stronger varieties, such as sinsemilla. Concentrations in cannabis resin, which is extracted from herbal cannabis, increased by 24% between 1975 and 2017.
This was the equivalent of a 5mg increase in THC per annum. One 5mg dose is enough for mild intoxication, according to the…