“Excessive fear and anxiety, coupled with corticolimbic dysfunction, are core features of stress- and trauma-related psychopathology, such as posttraumatic stress disorder (PTSD).
Interestingly, low doses of ∆9-tetrahydrocannabinol (THC) can produce anxiolytic effects, reduce threat-related amygdala activation, and enhance functional coupling between the amygdala and medial prefrontal cortex and adjacent rostral cingulate cortex (mPFC/rACC) during threat processing in healthy adults.
Together, these findings suggest the cannabinoid system as a potential pharmacological target in the treatment of excess fear and anxiety. However, the effects of THC on corticolimbic functioning in response to threat have not be investigated in adults with trauma-related psychopathology.
OBJECTIVE:
To address this gap, the present study tests the effects of an acute low dose of THC on corticolimbic responses to threat in three groups of adults: (1) non-trauma-exposed healthy controls (HC; n = 25), (2) trauma-exposed adults without PTSD (TEC; n = 27), and (3) trauma-exposed adults with PTSD (n = 19).
METHODS:
Using a randomized, double-blind, placebo-controlled, between-subjects design, 71 participants were randomly assigned to receive either THC or placebo (PBO) and subsequently completed a well-established threat processing paradigm during functional magnetic resonance imaging.
RESULTS:
In adults with PTSD, THC lowered threat-related amygdala reactivity, increased mPFC activation during threat, and increased mPFC-amygdala functional coupling.
CONCLUSIONS:
These preliminary data suggest that THC modulates threat-related processing in trauma-exposed individuals with PTSD, which may prove advantageous as a pharmacological approach to treating stress- and trauma-related psychopathology.”
https://www.ncbi.nlm.nih.gov/pubmed/32162103
https://link.springer.com/article/10.1007%2Fs00213-020-05499-8
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“The behavioural effects elicited by chemical constituents of Cannabis sativa, such as 
“Posttraumatic Stress Disorder (PTSD) is a leading psychiatric disorder that mainly affects military and veteran populations but can occur in anyone affected by trauma. PTSD treatment remains difficult for physicians because most patients with PTSD do not respond to current pharmacological treatment. Psychotherapy is effective, but time consuming and expensive. Substance use disorder is often concurrent with PTSD, which leads to a significant challenge for PTSD treatment.
“This review is to summarize most recent evidence published in the last 18 months on medical and recreational use of cannabis and 
“Post-traumatic stress disorder sharply increases the risk of depression and suicide. Individuals living with post-traumatic stress disorder frequently use cannabis to treat associated symptoms.
“The role of the endocannabinoid system in stress-related psychiatric symptoms has been investigated in many animal and human studies.
“Preclinical studies have shown that cannabidiol (CBD) mitigates fear memories by facilitating their extinction or interfering with their generalization and reconsolidation. The brain regions and mechanisms underlying these effects, and their temporal window, are still poorly understood. The present paper aimed at investigating related questions in the dorsal hippocampus (DH) during contextual fear consolidation.