More than 5 million people suffer from symptoms of post-traumatic stress disorder (PTSD) annually, and new research suggests that cannabis may help them find relief and may even offer better care than the current class of drugs commonly used to treat the disorder.
According to research published in the journal Neuropsychopharmacology, the administering of synthetic cannabinoids to rats after a traumatic event can prevent behavioral and physiological symptoms of PTSD by triggering changes in brain centers associated with the formation and holding of traumatic memories.
The study adds to a growing body of research that "contributes to the understanding of the brain basis of the positive effect cannabis has on PTSD," the researchers note.
While cannabinoids occur naturally in the cannabis plant, this research was done with WIN 55,212-2, a synthetic cannabinoid that produces a similar, effect to that of THC, marijuana's main psychoactive compound. The researchers specifically looked at the effect of this synthetic cannabinoid on exposure to trauma reminders. Among individuals who suffer from trauma, it is common for non-traumatic events (for instance, sirens going off) to evoke the memory of the traumatic event, thus amplifying the negative effects of the trauma.
In the first part of the experiment, the researchers exposed rats to a traumatic event (electric shock). After the trauma, some of the rats were injected with the synthetic cannabinoid compound. On the third and fifth days of the trial, the rats were exposed to 'trauma reminders' which triggered memories of the electric shock. Then, the rats went through a trauma 'extinction procedure,' a process similar to exposure therapy, designed to help them cope with post-trauma symptoms.
The researchers found that after being exposed to the trauma reminders, the rats injected with synthetic cannabinoids did not exhibit PTSD symptoms such as impaired extinction learning, increased startle response, changes in pain sensitivity and impaired plasticity in the brain's reward center. The control group of rats who were not administered the substance, however, did experience these symptoms. The treated rats also fared better after the trauma reminders than a group of rats administered with the SSRI antidepressant sertraline (Zoloft), a substance which has been used in the treatment of PTSD with mixed success in reducing symptoms.
The researchers also determined the neurological basis for these behavioral effects. They found that among the rats who were exposed to trauma and trauma reminders, there was an increase in the expression of two brain receptors associated with emotional processing (the CB1 and GR receptors). The compound actually prevented the increase in expression of these two receptors in two brain areas involved in forming and saving traumatic memories, the hippocampus and the prefrontal cortex.
One of the study's lead authors, Dr. Irit Akirav, previously found a synthetic marijuana compound to be effective in reducing PTSD symptoms in rats if administered within 24 hours of the traumatic event itself. Now, Akirav's new research suggests that marijuana may also be an effective intervention at the later trauma-reminder stage.
While the research is preliminary, it does suggest that human trials should be conducted to examine marijuana's promise as a treatment option for PTSD.
"The findings of our study suggest that the connectivity within the brain's fear circuit changes following trauma, and the administration of cannabinoids prevents this change from happening," the researchers concluded. "This study can lead to future trials in humans regarding possible ways to prevent the development of PTSD and anxiety disorders in response to a traumatic event."
And in recent years, there has been an increase in focus on the potential benefits cannabis may have for veterans suffering from PTSD.
Nearly 30 percent of veterans who served in the Iraq and Afghanistan wars suffer from PTSD, according to a 2012 VA report. Some scientists have suggested that marijuana may help PTSD symptoms, which can include anxiety, flashbacks and depression. In a recent study, patients who smoked cannabis saw an average 75 percent reduction in PTSD symptoms.