Approaching a treatment for marijuana addiction
The number of past-month marijuana users in the U.S. in 2012 was approximately 18 million, compared to 1.6 million cocaine and 0.3 million heroin users . Although estimates from research show that dependence rates for marijuana are lower than for cocaine or heroin (9 percent versus 17 and 23 percent, respectively), higher marijuana usage means that marijuana dependence is more prevalent than dependence on cocaine or heroin . Despite a clear need, there are currently no FDA-approved medications to treat marijuana addiction.
IRP researchers led by Zuzana Justinova, M.D., Ph.D., and Steven R. Goldberg, Ph.D., discovered that enhancing levels of kynurenic acid in two reward-related brain areas, the nucleus accumbens (NAc) and the ventral tegmental area (VTA), of an animal model significantly reduced the neurochemical and behavioral effects of delta-9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis.
The team’s finding suggests that modulation of kynurenic acid levels could be a pharmacological strategy for achieving abstinence from cannabis and preventing relapse.
Justinova Z, Mascia P, Wu HQ, Secci ME, Redhi GH, Panlilio LV, Scherma M, Barnes C, Parashos A, Zara T, Fratta W, Solinas M, Pistis M, Bergman J, Kangas BD, Ferré S, Tanda G, Schwarcz R, Goldberg SR. (2013). Reducing cannabinoid abuse and preventing relapse by enhancing endogenous brain levels of kynurenic acid. Nat Neurosci. 16(11), 1652-61.