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Emily Earlenbaugh Contributor
PTSD patients have been saying for years that cannabis helps with their PTSD. This debilitating condition causes chronic problems like nightmares, panic attacks, hypervigilance, detachment from others, overwhelming emotions, and self-destructive behavior. In some cases, these overwhelming symptoms can even lead to suicide. And while research on the topic has been somewhat inconclusive, many PTSD patients continue to report that cannabis does help.
Now, new research suggests the biological mechanisms behind this therapeutic effect.
Two recent studies point to the way that cannabinoids may help treat PTSD. One shows how cannabis can reduce activity in the amygdala - a part of the brain associated with fear responses to threats. Meanwhile, another suggests that the plant’s cannabinoids could play a role in extinguishing traumatic memories. Both effects could be therapeutic for those suffering from PTSD - according to recent studies.
One study, from researchers at Wayne State University in Detroit, MI, looked at how cannabis use impacts the amygdala response of those dealing with trauma related anxiety, such as PTSD. Previous research has shown that cannabis has the potential to reduce anxiety, or even prevent heightened anxiety in threatening situations. But up to this point, no studies had investigated this response in adults dealing with trauma - such as those with PTSD.
The Wayne State University study took on this challenge, and studied the amygdala responses in three groups of participants - healthy controls who had not been exposed to trauma, trauma exposed adults without PTSD and trauma exposed adults with PTSD. Using a randomized, double-blind procedure, the 71 participants were either given a low dose of THC or a placebo. Then they were exposed to threatening stimuli and their amygdala responses were recorded.
Those exposed to THC had lowered threat-related amygdala reactivity.
This means that those who took low doses of THC showed measurable signs of reduced fear and anxiety in situations designed to trigger fear. Since these results were found in all three groups, it suggests that even those with PTSD were able to experience less fear with THC in their system.
A second study, from researchers at Brazil’s Federal University of Parana, explored another potential way that cannabis could help those with PTSD - extinguishing the intensity associated with memories of their trauma. This mode of treating PTSD was first hypothesized by Yale associate professor of psychiatry R. Andrew Sewell who suggested that cannabis may be able to help PTSD patients “overwrite” traumatic memories with new memories in a process called ‘extinction learning’.
In an interview with East Bay Express, Sewell explained that the extinction learning process usually helps trauma resolve on its own. He gave the example of an Iraq War Veteran who gets PTSD symptoms while driving under bridges - after dodging explosives thrown down from bridges during the war. "Suppose some part of your reptile brain thinks if you walk under a bridge you're going to die," Sewell explained "life becomes very hard."
For most who experience traumatic incidents, these fears subside after 6 months or so because of the extinction learning process. New memories of the traumatic trigger form and override the old. Someone with a traumatic experience of explosives being dropped from bridges, may at first feel terrified as they approach any bridge - with traumatic memories flooding their mind. But after months of nothing bad happening around bridges, most will begin to feel bridges are less dangerous, as many memories of driving under bridges safely accumulate. The old memories still linger, but they don’t cause the increase in fear when the trigger (like the bridge) is present. So while most with trauma remember the traumatic incidents, those memories no longer trigger intense fear.
But for those with PTSD, extinction learning doesn’t happen. The trauma attached to the old memories continues to cause problems.
Still, Sewell believed that cannabis could help. Cannabis stimulates CB1 - a receptor in the endocannabinoid system that Sewell says has improved extinction learning in animal studies. Interestingly, those with PTSD show impaired functioning of the endocannabinoid system - which may be why they are unable to go through the normal extinction learning process.
Sewell theorized that cannabis might be able to jump start this process - allowing those with PTSD to access extinction learning like their healthy counterparts, and curing the PTSD by helping them to move on from their trauma. Unfortunately, he was unable to complete his research before he unexpectedly passed away in 2013.
But this recent study from Brazil’s Federal University of Parana looks deeper into the question. These researchers conducted a thorough review of the cannabis literature from 1974-2020 looking for evidence from controlled human trials to support or refute the theory that cannabis helps with ‘extinction’ of traumatic memories.
The researchers found that cannabis could help. Low doses of the cannabinoid THC or THC combined with another cannabinoid CBD were both able to enhance the extinction rate for challenging memories - and reduce overall anxiety responses. From their study, it seems that THC drives the extinction rate improvements, while CBD can help alleviate potential side effects from higher doses of THC.
The authors conclude that the current evidence from both healthy humans and PTSD patients suggests that these forms of cannabis “suppress anxiety and aversive memory expression without producing significant adverse effects.”
These studies provide some answers about why cannabis is helping PTSD patients feel better - both immediately and in the long run. Still, future studies may help clarify a range of questions about how and when to use cannabis effectively for PTSD, and whether there are risk factors associated with using the drug for this condition.