Alzheimer's Disease Health Center

Marijuana May Slow Alzheimer's

Oct. 6, 2006 -- THC, the key compound in marijuana, may also be the key to new drugs for Alzheimer's disease.

That's because the marijuana compound blocks the formation of brain-clogging Alzheimer's plaques better than current Alzheimer's drugs.

The finding -- in test-tube studies -- comes from the lab of Kim Janda, PhD, director of the Worm Institute of Research and Medicine at Scripps Research Institute.

"While we are certainly not advocating the use of illegal drugs, these findings offer convincing evidence that THC possesses remarkable inhibitory qualities, especially when compared to [Alzheimer's drugs] currently available to patients," Janda says in a news release.

"Although our study is far from final, it does show that there is a previously unrecognized molecular mechanism through which THC may directly affect the progression of Alzheimer's disease."

Janda's team found that THC blocks an enzyme called acetylcholinesterase, which speeds the formation of amyloid plaque in the brains of people with Alzheimer's disease.

The Alzheimer's drugs Aricept and Cognex work by blocking acetylcholinesterase. When tested at double the concentration of THC, Aricept blocked plaque formation only 22% as well as THC, and Cognex blocked plaque formation only 7% as well as THC.

"THC and its analogs may provide an improved [treatment for] both the symptoms and progression of Alzheimer's disease," the researchers conclude.

The findings appear in the Aug. 9 online edition of the journal Molecular Pharmaceutics, a publication of the American Chemical Society.