There is a huge amount of empirical evidence that adverse childhood experiences disrupt the HPA-axis as well as other biological systems. It's also well-known that people with PTSD have low cortisol. These aren't controversial findings. They've been found over and over.

I have CPTSD and it's very clear to me that the symptoms of this "mental disorder" are in my body, first and foremost. And it's clear that after I go through a flashback, I'll end up going through symptoms that many would describe as chronic fatigue syndrome or adrenal fatigue. So I don't think the comment is to say "It's all in your head", but to say that the mind and body are actually connected. (Shocking!) It's a two-way street. I'm actually relieved to see a medical professional say something that I've been thinking for the past few years.