What the review found
Bloomfield and colleagues brought together animal and human research on THC and dopamine. Acute exposure can increase dopamine activity, while longer-term cannabis use has been associated with reduced aspects of dopamine function. The review describes conflicting results and a complex relationship, rather than one mechanism that explains every experience of cannabis. Original review.
What remains uncertain
An association with long-term use does not establish that an individual has permanent damage. This review also does not supply a validated dopamine-recovery schedule after stopping cannabis. Recovery of a different measure, such as CB1 receptor availability, cannot be treated as a direct measurement of dopamine recovery.
Read the original research
The effects of Δ9-tetrahydrocannabinol on the dopamine system.
Nature
Nature is the most prestigious multidisciplinary science journal in the world.
Citation
Michael A P Bloomfield; Abhishekh H Ashok; Nora D Volkow; Oliver D Howes. (2016). The effects of Δ9-tetrahydrocannabinol on the dopamine system.. Nature. https://doi.org/10.1038/nature20153