The first study to investigate changes in cannabis across Europe showed that cannabis resin and herbal cannabis have significantly increased in potency and in price. The study was published on 30 December 2018 in the journal Addiction by researchers from the University of Bath and King’s College London. It draws on data collected from across 28 EU Member states, as well as Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction.
The findings show that for herbal cannabis, concentrations of Δ9-tetrahydrocannabinol (‘THC’ – the main psychoactive constituent of cannabis) increased by a similar amount each year, from 5% in 2006 to 10% in 2016.
For cannabis resin, THC concentrations were relatively stable from 2006 to 2011 (from 8% to 10%) but then increased rapidly from 2011 to 2016 (from 10% to 17%). The price of cannabis resin also increased, but to a lesser extent than for herbal cannabis.
Cannabis resin typically contains cannabidiol (CBD) in addition to THC. CBD has recently attracted considerable interest due to its potential to treat several medical conditions including childhood epilepsy syndromes, psychosis and anxiety. But, when present in cannabis, CBD may offset some of the harmful effects of THC such as paranoia and memory impairment.
Cannabis-containing higher levels of THC and/or lower levels of CBD has been linked to greater long-term harms such as the development of cannabis dependence, and an increased risk of psychotic illness. New resin production techniques in Morocco and Europe have increased levels of THC, but not CBD.
Leader of the research team Dr Tom Freeman indicates that “CBD has the potential to make cannabis safer, without limiting the positive effects users seek. What we are seeing in Europe is an increase in THC and either stable or decreasing levels of CBD, potentially making cannabis more harmful. These changes in the illicit market are largely hidden from scientific investigation and are difficult to target by policy-makers. An alternative option could be to attempt to control THC and CBD content through regulation.”
The research is available following this link>>>>