In a new study from the University College London (UCL), a team of researchers focused on the difference between consuming cannabis strains that have high levels of THC, and strains that have significant quantities of both THC and CBD.
The precise effects on the brain were monitored by an fMRI (functional magnetic resonance imaging), which measures changes in blood flow and neural activity.
Brain scans of the 17 participants showed that the high-THC strain impaired the functionality of the default mode network, especially in the posterior cingulate area.
The dysfunctionality of the posterior cingulate area closely corresponded with the sensation of “being high”, showing that the effects of THC on this section are connected with the cerebral intoxication of cannabis.
The high-THC strain also caused disruption to the salience network, which determines what sensory or emotional information we focus on at a given time.
Improper functioning of the salience network was already connected with psychosis and addiction prior to this study.
Unlike the strain which only contained high levels of THC, the strain that also had high levels of CBD caused minimal disturbances to these regions of the brain.
The results of this study support the theory that the CBD cannabinoid (when used in combination with THC) diminishes the negative effects of THC, including the psychoactivity caused by tetrahydrocannabinol, while adding to the medicinally beneficial effects.
Dr. Matt Wall (the leading author of the study), comments:
“Over the last two decades, rates of addiction and psychosis linked to cannabis have been on the rise, while at the same time stronger strains of cannabis with more THC and less CBD have become increasingly common.
“We have now found that CBD appears to buffer the user against some of the acute effects of THC on the brain.”