Our paper entitled “Legalization, Decriminalization & Medicinal Use of Cannabis: A Scientific and Public Health Perspective” by Svrakic DM, Lustman PJ, Mallya A, Taylor AL, Finney R & Svrakic NM, published in the March/April 2012 issue of Missouri Medicine cites the study by Stokes et al (2010) as demonstrating “decreased levels of cortical dopamine after THC challenge” (p. 94). In fact, Stokes et al (2010) show significant decreases in frontal and temporal [11C]-raclopride binding after THC challenge, thus demonstrating increased dopamine release after THC challenge. Note however that this miscitation of Stokes et al (2010) does not undermine the argument that cannabis causes cognitive dulling and impairments. Following an inverse “U” shape pattern, prefrontal cortex function is optimal at intermediate levels of dopamine (Winterer & Weinberger, 2004) and is impaired in states of dopaminergic hypofunction (e.g., patients with Parkinson’s disease) and hyperfunction (e.g., in amphetamine-induced psychosis). THC clearly alters prefrontal and temporal dopamine release, and this shift could be one of the mechanisms underlying well documented cognitive impairments in cannabis users.
Literature
- Stokes PRA, Egerton A, Watson B, et al. Significant decreases in frontal and temporal [11C]-raclopride binding after THC challenge. Neuro Image. 2010;52:1521–1527. doi: 10.1016/j.neuroimage.2010.04.274. [DOI] [PubMed] [Google Scholar]
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