Data gathered from more than 80,000 street samples gathered over the last 50 years shows THC potency has dramatically risen.
By Abu Khalil
Photo by Altaf Qadri
Hashish – the resin extracted from cannabis– or “hash” – has become markedly more potent over the past 5 decades. An international study demonstrates that the average sample is 25% stronger.
Scientists with the Addiction and Mental Health Group at the University of Bath evaluated data from 80,000+ samples tested over the last half-century in the US, UK, Netherlands, France, Denmark, Italy and New Zealand.
They published their conclusions in the journal Addiction which show that concentrations of the psychoactive cannabinoid THC have steadily increased every decade.
In cannabis flower — or “buds” — THC potency grew by 14% between 1970 and 2017. This is largely attributed to the increased prevalence of ‘danker’strains and tailored breeding. THC concentrations in hash grew by 24% between 1975 and 2017.
Simply said, THC potency increases about 5mg every year. For rookies, smoking or ingesting 5mg more than adequate to attain a mild ‘buzz.’
“Cannabis has continued to increase in strength over time, such that today it differs enormously from the type of drug used by people 50 years ago,” wrote researcher Dr. Tom Freeman. “During this time attitudes have also shifted. There is now a greater appreciation of its complex interplay with mental health and potential medicinal uses.”
“Cannabis resin is often seen as a safer type of cannabis, but our findings show that it is now stronger than herbal cannabis,” wrote study co-author Sam Craft. “Traditionally, cannabis resin contained much lower amounts of THC with equal quantities of CBD (cannabidiol, which is believed to have some health benefits), however CBD concentrations have remained stable as THC has risen substantially, meaning it is now much more harmful than it was years ago.”
Cannabis is the most frequently consumed ‘drug’ in the world yet has enjoyed legalization and/or decriminalization in much of the world.
The advocates for controls and labeling of cannabis strength in ways not dissimilar to methods used for alcohol.
The study went further to recommend users select strains with lower THC content or greater quantities of the non-psychoactive cannabinoid CBD: “Current evidence‐based Lower Risk Cannabis Use Guidelines  recommend that consumers should choose products with low concentrations of THC or a balanced level of THC and CBD. As information on THC and CBD concentrations is not available to consumers in most jurisdictions, monitoring studies provide an essential tool for assessing the possible health effects of different products and how they change over time,”
“As the strength of cannabis has increased, so too has the number of people entering treatment for cannabis use problems,” Freeman wrote. “More Europeans are now entering drug treatment because of cannabis than heroin or cocaine.”