There is evidence that chronic (persistent) stress may actually rewire your brain, says Dr. Ressler. Scientists have learned that animals that experience prolonged stress have less activity in the parts of their brain that handle higher-order tasks — for example, the prefrontal cortex — and more activity in the primitive parts of their brain that are focused on survival, such as the amygdala. It's much like what would happen if you exercised one part of your body and not another. The part that was activated more often would become stronger, and the part that got less attention would get weaker, he says. This is what appears to happen in the brain when it is under continuous stress: it essentially builds up the part of the brain designed to handle threats, and the part of the brain tasked with more complex thought takes a back seat.
These brain changes may be reversible in some instances, says Dr. Ressler, but may be more difficult to reverse in others, depending on the type and the duration of the stress. While stressful childhood experiences seem to take more of a toll on the developing brain, some research has found that people who demonstrate resilience in the face of past childhood trauma actually appear to have generated new brain mechanisms to compensate. It's thought that these new pathways help to overcome stress-related brain changes that formed earlier in life, he says.
