Hmmm complicated answer but, in short, PTSD results from a dysfunctional endocannabinoid system.
To understand the neurobiological mechanisms of PTSD, scientists analyzed 46 subjects, half of whom had PTSD and half who did not. Researchers found that people with PTSD had lower blood levels of anandamide, a cannabis-like compound that we produce in our bodies.
In all mammals, anandamide triggers the same brain receptors that are activated by THC. The cannabinoid receptor, CB1, found in our brain and central nervous system is involved in emotional learning, stress adaptation and fear extinction. Researchers have found that normal CB1 receptor signaling deactivates traumatic memories and allows us to …… forget.
Low levels of anandamide affects CB1 signaling and results in impaired fear extinction, aversive memory consolidation and chronic anxiety, all seen in patients with PTSD.
Cannabis activates these CB1 receptors.