The body of scientific cannabis research continued to grow rapidly in 2025, with more than 4,000 studies published during this year — for the 5th consecutive year.
According to NORML’s results of a search of PubMed.gov/National Library of Medicine, over 37,000 papers have been published on cannabis in the past decade.
NORML reports that “over 90 percent” of peer-reviewed papers on marijuana were published after 2002. PubMed.gov, as of the time this article was written, cited over 53,000 marijuana-related papers dating all the way back to 1840.
See the results yourself try this search on PubMed. The results page has additional filters to narrow the list of studies.
William Brooke O’Shaughnessy’s 1842 series of articles describing hemp’s use in treating children’s muscular spasms was one of the earliest papers ever published on cannabis. Jean-Jacques Moreau de Tours, a researcher who focused on mental disorders, published research in 1845 on cannabis’ effects on the brain.
Only 211 publications were published between 1843 and 1966. In the 60’s, and up until the mid 70’s there were close to 3,500 papers published. After that, publishing dropped until the start of this century. From then on it accelerated.
The constant call for “more” research is one thing that holds back progress in cannabis regulation and policy. It’s like kicking the can down the road. NORML Deputy Director Paul Armentano echoed last year’s comments on this mindset. stating:
“It is time for politicians and others to stop assessing cannabis through the lens of ‘what we don’t know’ and instead start engaging in evidence-based discussions about marijuana and marijuana reform policies that are indicative of all that we do know.”
It is important to note that just because there are so many research studies available today, does not necessarily mean consensus on all issues. Recent research analyzing randomised clinical trials has revealed that there is still considerable disagreement about the benefits of medical cannabis.