I've never heard that in all my reading and research. Anxiety and depression create a toxic environment where proper brain function can be disrupted. The purpose of the vitamin regimen is to help the brain cleanse of the toxins and maintain a toxin free function. There is concern that PTSD may cause physical damage to the brain during the precipitating trauma.

So, yes, anxiety and depression can be just as toxic as a concussion but the toxicity does not cause permanent damage. That toxicity will delay recovery from the concussion. The brain tissue needs a healthy environment to heal properly. That is why it is so important to resolve anxiety issues.

Research shows a shrinking of the hippocampus that they believe is due to cortisol, a steroid hormone related to stress. When this cortisol level is reduced and serotonin increases, this shrinkage can reverse.

btw, You have your term wrong. It is neuroDEgenerative disease. It causes the brain to degenerate or atrophy/shrink. Depression could be considered a neurodegenerative disease.