In 2011, Neural basis of anxiolytic effects of cannabidiol (CBD) in generalized social anxiety disorder: using functional neuroimaging. a preliminary report.

BACKGROUND: Regional cerebral blood flow (rCBF) at rest was measured twice using (99m)Tc-ECD SPECT in 10 treatment-naïve patients with SAD. In the first session, subjects were given an oral dose of CBD (400 mg) or placebo, in a double-blind procedure. In the second session, the same procedure was performed using the drug that had not been administered in the previous session. Within-subject between-condition rCBF comparisons were performed using statistical parametric mapping.

You can read the full article here => https://www.ncbi.nlm.nih.gov/pubmed/20829306