Distinct Effects of 9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing

The plant Cannabis contains multiple compounds that likely possess distinct psychoactive properties. In fact, 9-Tetrahydrocannabinol (THC) and CBD, the two major constituents, were recently demonstrated to influence anxiety response – at neural, physical and behavioral levels – in contrasting ways.

In this research study, scientists measured the regional brain activation using fMRI and electrodermal activity of participants who were viewing fearful faces that elicited various levels of anxiety. Prior to measurement, these participants were randomly assigned to ingest THC, CBD, or a placebo. Following the measurement, objective and subjective ratings of various symptoms were also completed.

fMRI data indicated that CBD attenuated the activation of limbic and paralimbic regions of the brain, including the amygdala, the anterior and posterior cingulate cortex while participants observed anxiety-inducing faces. Meanwhile, THC mainly modulated the activation of frontal and parietal areas of the brain. Electrodermal activity data showed that fluctuations in autonomic arousal – a physical component of anxiety – decreased following administration of CBD while increased following administration of THC. Symptom ratings suggested that THC increased levels of anxiety, intoxication, and psychotic symptoms. CBD didn’t induce a significant effect compared to placebo, although there was a trend for anxiety reduction.

In short, researchers concluded that the reduction of limbic and paralimbic brain activation by CBD contributes to its ability to soothe physical arousal and subjective symptoms of anxiety, whereas the anxiety-inducing effects of THC are related to its activation of other regions, likely the frontal and parietal areas.

What have your experiences been with blending CBD and THC? Has it helped your anxiety or stress? We’d love to hear your experience!


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