A new study conducted at eleven sites in five countries across Europe, as well as one in Brazil, has found that consuming cannabis daily triples the chances of a person developing psychosis. The risk reportedly becomes five-fold if potent cannabis (with high levels of THC) is taken every day.
Researchers found that the link with psychosis was strongest in cities like Amsterdam and London, where one can easily get high-potency cannabis.
For the study – which took place in England, Italy, France, the Netherlands, Spain, and BraziI – researchers looked at the drug use history of around 900 patients experiencing a first psychotic episode between 2010 and 2015, and 1,237 healthy individuals.
It was concluded that nearly 29.5% of the patients had a habit of consuming cannabis daily, while only 6.8% of the healthy lot were accustomed to the same. In addition, over a fifth of the psychosis cases were thought to be linked to daily cannabis use across the 11 sites, according to the journal The Lancet Psychiatry.
Lead researcher Dr. Marta Di Forti, from King’s College London, asserted that her findings are consistent with previous studies showing that the use of cannabis with high levels of THC has more harmful effects on mental health than the use of weaker forms.
Notably, strong forms of marijuana – commonly known as ‘skunk’ – containing as high as 14% THC now account for 94% of the drugs being sold on the streets of London, reports Rte(.ie).
The legalization drive of medical (and recreational) cannabis is gaining a lot of speed in 2019. In the U.S., recreational cannabis is now legal in 10 states.
However, before passing any legalization bill, the lawmakers should also consider the effects of long-term use of daily cannabis, especially the ones containing high amounts of THC, which may do more harm than good.