“Exposure to excessive or uncontrolled stress is a major factor associated with various diseases including post-traumatic stress disorder (PTSD). The consequences of exposure to trauma are affected not only by aspects of the event itself, but also by the frequency and severity of trauma reminders. It was suggested that in PTSD, hippocampal-dependent memory is compromised while amygdala-dependent memory is strengthened.

Several lines of evidence support the role of the endocannabinoid (eCB) system as a modulator of the stress response.

In this study we aimed to examine cannabinoids modulation of the long-term effects (i.e., 1 month) of exposure to a traumatic event on memory and plasticity in the hippocampus and amygdala.

Cannabinoids prevent the differential long-term effects of exposure to severe stress on hippocampal- and amygdala-dependent memory and plasticity.

Taken together, these findings suggest the involvement of the endocannabinoid system, and specifically CB1 receptors, in the opposite effects of severe stress on memory and plasticity in the hippocampus and amygdala.”  https://www.ncbi.nlm.nih.gov/pubmed/28667676

http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002/hipo.22755