Synthetic cannabinoids can increase depression- and anxiety-like behaviors in a rodent model of trauma, according to new research in European Neuropsychopharmacology.

“Brenda Sbarski, one of my master students, was very much interested to find out how pre-trauma exposure to cannabinoids affect the response to a traumatic event. All of our studies were conducted on rats with no prior exposure to cannabinoids (before the trauma) and she thought that this may not represent the human condition correctly,” said study author Irit Akirav of the University of Haifa.

The researchers were interested in learning whether chronic exposure to a cannabinoid receptor agonist before experiencing trauma would have a therapeutic effect or would exacerbate the negative consequences of trauma.

In their experiments, rats were administered the synthetic CB1/2 receptor agonist WIN55,212–2 for twelve days before being subjected to an inescapable electric shock.

Exposure to the cannabinoid receptor agonist enhanced fear retrieval and impaired fear extinction, and also increased immobility in a forced swimming test — behaviors that reflect anxiety and depression, respectively. But it was also found to have a therapeutic effect in a startle test.

The key finding is that “chronic exposure to drugs that activate CB1 receptors before being exposed to a traumatic event might have deleterious effects on the emotional response to the trauma (compared to subjects that were not expose to cannabinoids before the trauma),” Akirav told PsyPost.

“We need to study what happens when we administer cannabinoids after trauma exposure to subjects that were already exposed to cannabinoids before trauma exposure. Will they need a different treatment than the non pre-trauma exposed subjects?”

“The effects may be specific to CB1 receptor activation,” she added. “It could be that other cannabinoids (not directly activating the CB1 receptor) may have different (better?) effects on the response to the trauma.”

The study, “Chronic exposure to cannabinoids before an emotional trauma may have negative effects on emotional function“, was authored by Brenda Sbarski and Irit Akirav.