Making Sense of PTSD’s Emotional Numbing

Building on some of the storied institution’s earlier research, a group of Yale researchers might have discovered a new approach to treating those struggling with post-traumatic stress disorder (PTSD).

Earlier studies established that the amygdala reacts differently to mild physical or emotional pain (it’s less sensitive). And now new research appears to have clarified that response (or lack thereof).

In a new paper, Yale researchers explain that a particular neuromodulator system in the brain might be responsible for – or at least play a pivotal part – in this interaction.

Digging Deeper Into PTSD

The team found that PTSD patients displayed lower amygdala activity when reacting to mild electric shocks. The authors cited greater emotional numbing symptoms, such as restricted emotional expressions.

This newer research studied the role of the brain’s endocannabinoid (eCB) system, which is tied to pain regulation and stress-related disorders, such as PTSD. Using PET scans, the researchers measured the availability of CB1 receptors (CB1R) in the amygdala, a crucial part of the eCB system.

“The endocannabinoid system is crucial for pain modulation and is involved in stress-related disorders like PTSD,” Nachshon Korem, an associate research scientist at Yale School of Medicine (YSM) and lead author of the study, explained. “Based on our earlier findings, we suspected it might contribute to this low reactivity of the amygdala.”

What they found was a strong negative correlation between CB1R availability and the brain’s pain response. They also noted a positive association between CB1R availability and the severity of emotional numbing in PTSD patients.

“We found that the more cannabinoid receptor 1 availability was in the amygdala, the less reactive the amygdala was to mild pain and the more emotional numbing symptoms a person presented,” Korem added. “Endocannabinoids have a large inhibiting effect on the amygdala, and here it seems that when there is more receptor availability, endocannabinoids can suppress the amygdala’s response to mild pain more strongly.”

What it Means

The findings suggest that higher CB1R availability, suggestive of lower eCB activity, could contribute to lower pain sensitivity and higher emotional numbing in PTSD patients. The study highlights the potential therapeutic role of the eCB system in treating pain and emotional dysregulation in PTSD.

Researchers have known that PTSD patients can endure a range of emotional sensitivity. And earlier studies have hinted that emotional under-expressions could build into an amplified response later. This paper sheds new light on the phenomenon of emotional under-expression. This could pave the way for a new treatment approach.

“If you can help people with PTSD have appropriate reactions to smaller irritations, maybe it would prevent the sort of all-or-nothing responses common in the disorder,” Korem said. “The endocannabinoid system might be a target for that type of treatment.”

Further Reading

Why FDA Panel Rejected MDMA for PTSD Treatment

What Does a Systematic Review of Cannabis and PTSD Tell Us?

Training for Lasting Trauma-Informed Change