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Volume 539 Number 7629 pp330-462
17 November 2016
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About the cover
A Seattle cannabis worker cradles the resin-dusted bud of a strain called Blueberry Cheesecake. The legalization of marijuana has become a topic of debate in the United States and recent reports suggest that cannabis has now overtaken heroin as the most reported illicit drug in users seeking specialist addiction care in Europe. However, there are stark differences in the scientific literature as to how Δ9-tetrayhydrocannabinol (THC), the psychoactive compound in marijuana, affects neural networks, such as the dopamine-driven reward system. In this issue of Nature, Michael Bloomfield et al. review the conflicting evidence between clinical and animal research studies. They conclude that THC exposure produces complex and potentially long-term effects on the dopamine system including increased nerve firing and dopamine release in response to acute THC, and dopaminergic blunting associated with long-term use. Future research, they suggest, should focus on the relationships between cannabis-induced alterations in the dopamine system and behavioural effects in humans and animal models. Cover : Lynn Johnson/National Geographic Creative
