Difference of the Sexes: Endocannabinoids and Traumatic Memories


Andrei Nastase

Principal Investigator

Dr. Matthew Hill


University of Calgary

Grant Type



Post-Traumatic Stress Disorder (PTSD)

About the researcher

Andrei Nastase

Undergraduate Student at the University of Calgary

The impact

All of us have bad memories, moments where we were really scared and frightened. Most of us are shaken up by these experiences, but eventually move on. People with Post-Traumatic Stress Disorder (PTSD) are thought to have a biological susceptibility that makes it more difficult for them to move on from traumatic experiences compared to other people. Since PTSD is fundamentally about fear-based memories, neuroscientists have been investigating how the brain learns and forgets about scary memories. Understanding this could hold the key to helping people recover from their PTSD.  

The study

Endocannabinoids are the chemical system in our brain that Marijuana works on, with receptors found throughout the brain, particularly in areas related to emotions. Important for this study, there are differences in the endocannabinoid system between men and women, so this study looked at the expression of fear behaviours in rats after their endocannabinoid levels were raised. Males were unaffected by higher endocannabinoids, but females started expressing their fear responses in more male-like ways compared to normal, female-like ways.  

What's next?

This knowledge that endocannabinoids change the way fear is expressed in men and women is very useful to know when it comes to users of cannabis. Behaviours under stress may be changed in women during cannabis use, while they may remain unchanged in men (this finding would need to be replicated in humans to know for sure). Future studies can explore how these differences might contribute to PTSD and the potential for marijuana as a treatment option for it.  

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Morena, M., Nastase, A., Santori, A., Cravatt, B. F., Shansky, R. M., Hill, M. N. Sex-dependent effects of endocannabinoid modulation of conditioned fear extinction in rats. British Journal of Pharmacology. 2021; 178(4), 983–996. https://doi.org/10.1111/bph.15341