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 the results of a keyword search of the National Library of Medicine/PubMed.gov website by NORML, researchers have published more than 37,000 scientific papers on cannabis over the last decade.
“In all, more than 70 percent of all peer-reviewed scientific papers about marijuana have been published in the past ten years, and over 90 percent of this literature has been published since 2002,” says NORML. “As of this writing, PubMed.gov cites over 53,000 papers on marijuana dating back to 1840.”
To see the results for yourself, try this search on PubMed. Additional filters are available on the results page for narrowing down the studies.
Among the first papers on cannabis ever to be published were a series of articles by William Brooke O’Shaughnessy in 1842 describing the use of hemp for treating conditions such as muscular spasms in children. And in 1845, Jean-Jacques Moreau de Tours published research on the effects of cannabis on the mind, with a focus on treating mental disorders.
From 1843 to 1966, there were only around 211 papers published. But there was a surge in the 1960’s and into the mid-70’s with close to 3,000 papers. Publishing then dropped off again until the beginning of this century; and accelerated from around 2020.
Today, one of the issues holding back regulatory and other progress on cannabis are the constant calls for “more research”; kicking can down the road. Commenting on this continuing mindset, NORML’s Deputy Director Paul Armentano repeated his related thoughts from last year, 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.”
However, just because there is so much research now available, it doesn’t mean consensus has been achieved on a number of issues. A recent study analyzing randomized clinical trials revealed the considerable conflict that remains regarding the clinical benefits and otherwise of medicinal cannabis.
