According to CU Boulder psychiatry professor Christian Hopfer, marijuana is 5 times more stronger now than it was in the 1980s.
Hopfer is leading one of the biggest and most long term studies on the drug in history. At forthcoming $5.5 million, it is the largest marijuana study to date.
The professor told Business Insider that dispensaries in some states are selling marijuana that is “at least five times as strong” as it was forty years ago.
Hopfer has seen a variety of marijuana in dispensaries around Colorado that have a content breakdown of 25% THC. He said that before the content was 2-5%.
A study from researchers at the University of Mississippi found that THC content of marijuana in the United States has tripled since 1995. THC was around 4% in 1995 and in 2014 was 12%.
Hopfer has said that addressing cannabis and dosage need a new approach. He remarked, “I think we’ve dealt with marijuana historically from a criminal justice perspective, but if you switch to an environment where it’s legal, you switch to a public health perspective. And to do that right, we need more scientific research.”