Neuroscientists identify brain circuits linking cannabis to anxiety

Neuroscientists have identified the specific brain circuits responsible for the paradoxical anxiety, panic, and paranoia that can be triggered by cannabis use, particularly at high doses or in stressful environments. The research, published in Nature Communications, utilized animal models to observe how cannabinoids interact with fear responses.

In studies conducted by researchers from Western University and Northwestern University, mice were exposed to a predator-associated scent after receiving either a synthetic cannabinoid or a placebo. The mice treated with the cannabinoid exhibited increased defensive behaviors, such as freezing in place and reduced exploration.

Using miniaturized microscopes to monitor real-time brain activity, researchers localized the reaction to the central amygdala, a region dedicated to processing fear. The study found that cannabinoids specifically activate a small group of cells known as somatostatin neurons, making them more excitable. This activation appears to weaken the signals that normally regulate these cells, effectively removing a biological ‘brake’ on fear responses and leading to heightened anxiety when the subject is exposed to stressful stimuli.