Marijuana packs a lot more punch than it did 50 years ago, making it a greater threat to health, researchers say.
“As the strength of cannabis has increased, so too has the number of people entering treatment for cannabis use problems,” said study co-author Tom Freeman, director of the addiction and mental health group at the University of Bath in England.
In Europe, more people now enter drug treatment because of pot, than heroin or cocaine, Freeman said in a university news release.
He and his team assessed how concentrations of THC (the marijuana component that causes a high) has changed over time in different types of cannabis. They analyzed data from tests on more than 80,000 street samples collected in the United States, United Kingdom, Netherlands, France, Denmark, Italy, and New Zealand over the past 50 years.
THC concentrations in herbal cannabis increased by an average of 14% from 1970 to 2017, primarily due to a rise in stronger varieties, according to the authors.
They previously found that frequent use of cannabis with higher THC levels increases the risk of addiction and psychotic disorders.
The study also found particularly large THC increases in cannabis resin, with a 24% jump between 1975 and 2017. Cannabis resin is extracted from herbal cannabis and is now typically stronger than herbal cannabis, the researchers said.
“Cannabis…
