Common wisdom says depression starts in the mind with distorted thinking. But newer models suggest depression starts when the body initiates a defense strategy to help us survive.

If depression is the emotional expression of the immobilization response, then the solution is to move out of that state of defense. Porges believes it is not enough to simply remove the threat. Rather, the nervous system has to detect robust signals of safety to bring the social state back online. The best way to do that? Social connection.

For people who don’t prefer social connection, I’ve seen that exercise works well

Edit: just want to highlight that polyvagal theory, the main point behind this article, is unsubstantiated thus far

https://en.m.wikipedia.org/wiki/Polyvagal_theory