Marijuana given after extreme stress might prevent PTSD

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Synthetic marijuana that was given to rats after a traumatic event was able to block symptoms of PTSD after the rodents were exposed to extreme stress.

In a study conducted at the University of Haifa and published in the journal Neuropsychopharmacology, researchers found administering cannabinoids (synthetic marijuana) eliminated PTSD symptoms without erasing memory of the event.

Dr. Irit Akirav of the University of Haifa's Department of Psychology led the study.

Marijuana compounds block stress receptors in the brain

The scientists wanted to see if marijuana compounds could prevent PTSD in rats that are known to experience the same symptoms as humans.

The researchers exposed the animals to extreme stress, finding they reacted with increased startle reflex, and disruption of the neuroendocrine system.

The rats were divided into four groups. One group was untreated; the first group received a marijuana compound injection two hours after a traumatic event; the third group after 24 hours and the fourth group after 48 hours.

A week later, the researchers found rodents given the marijuana compound within 2 to 24 hours had no symptoms of PTSD compared to the other groups.

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All of the rats experienced anxiety, but symptoms of PTSD disappeared in the group given marijuana within the 2 or 24 hour time-frame

According to Dr. Akirav the “window of opportunity” for using cannabinoids for PTSD prevention in humans might be longer because humans have a longer lifespan.

He explains the finding “…indicates that the marijuana did not erase the experience of the trauma, but that it specifically prevented the development of post-trauma symptoms in the rat model.”

In a second experiment, the researchers injected marijuana directly into the region of the brain responsible for stress reaction to trauma - the amygdala.

The direct injection also blocked PTSD symptoms, leading the researchers to conclude marijuana blocks cannabinoid 1 (CB1) receptors in the brain and that those receptors play a role in developing PTSD.

The study authors write, “Cannabinoids have recently emerged as a possible treatment of stress- and anxiety-related disorders such as post-traumatic stress disorder (PTSD).”

Based on the finding, the authors concluded “cannabinoids could serve as a pharmacological treatment of stress- and trauma-related disorders.”

They also suggest there may be an optimal window of opportunity for administering the marijuana compound treatment. The study supports emerging research that cannabinoids might help prevent and treat PTSD.

Neuropsychopharmacology;|doi:10.1038/npp.2011.204
“Cannabinoids Prevent the Development of Behavioral and Endocrine Alterations in a Rat Model of Intense Stress”
Eti Ganon-Elazar and Irit Akirav
September 14, 2011

Image credit: Morguefile

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