Study Reveals Potential Cause of Marijuana's Anxiety-reducing Effects

Researchers have identified cannabinoid receptors in the region of the brain that regulates anxiety and the flight-or-fight response.

Scientists have demonstrated how cannabinoid receptors in the brain, which marijuana can affect, assist in the regulation of the fight-or-fight response in the amygdala, according to a study published in Neuron.

Researchers from Vanderbilt University used animal models to identify cannabinoid receptors in the central nucleus of the amygdala. After tagging the cannabinoid receptors with high-affinity antibodies, scientists used various microscopy techniques, including electron microscopy, to view individual synapses.

“We know where the receptors are, we know their function, we know how these neurons make their own cannabinoids,” Sachin Patel, MD, PhD, the paper’s senior author, said in a statement. “Now can we see how that system is affected by … stress and chronic (marijuana) use? It might fundamentally change our understanding of cellular communication in the amygdala.”

Patel also noted the results of this study may assist in explaining why chronic users of marijuana say they take the drug to reduce their anxiety. However, previous studies, including those conducted at Vanderbilt, have indicated that constant use of the drug down-regulates the cannabinoid receptors, which paradoxically increases anxiety over time. Patel explained that this process is a vicious cycle and can lead to addiction.

Another study showed anxiety can also be increased over time through chronic stress or acute, severe emotional trauma. Without the buffering effect of the production of endocannabinoids and the responsiveness of the receptors, anxiety can increase.