An interesting new theory for PTSD suggests that the root of the problem lies in context processing problems.
Context processing allows people and animals to recognize that a particular stimulus may require different responses depending on the context in which it is encountered. So, for example, a lion in the zoo evokes a different response than one encountered in your backyard.
The idea that a disruption in this circuit can interfere with context processing can explain most of the symptoms and much of the biology of PTSD. Previous models have focused on one aspect of the disorder:
- on abnormal fear learning, which is rooted in the amygdala
- on exaggerated threat detection, which is rooted in a network involving the amygdala, the anterior cingulate cortex and insula
- on executive function and emotion regulation, which is mainly rooted in the prefrontal cortex.
The researchers suggest that a deficit in context processing would lead PTSD patients to feel "unmoored" from the world around them, unable to shape their responses to fit their current contexts. Instead, their brains impose an "internalized context", one that always expects danger.
This type of deficit, arising from a combination of genes and life experiences, may create vulnerability to PTSD in the first place.
The researchers are now testing their model.
 . Context Processing and the Neurobiology of Post-Traumatic Stress Disorder. Neuron [Internet]. 2016 ;92(1):14 - 30. Available from: http://www.cell.com/neuron/abstract/S0896-6273(16)30640-7