A lot of the medication for psychological issues is aimed at altering the bio chemistry in the brain to mitigate physical problems. The reason that stuff works is because the issues are physical and not imagined. It's also true that certain disorders (e.g. psychosis) actually cause brain damage when left unchecked. This technically is not a single thing but more like a group of disorders with widely varying symptoms. My understanding is that a lot of PTSD complaints overlap in terms of symptoms and are probably related. Or that some PTSD patients actually become psychotic.

So not surprising to see some brain damage in navy seals. Of course the question is what comes first, the brain damage or the ptsd. And whether something can be done before brain damage happens in terms of medication or therapy.