I think there's something valid in that.
I said before I'm a 'been, there, done that' kinda guy, and I used to practise yoga, lived in a yoga centre for a few months, the Alexander Technique, Tai Chi, Felkenkrais....and more. All of those practises, to greater or lesser extent, recognise the mind-body link and how relaxing and changing muscular patterns does indeed change your mood. Tension around the chest is not good for your emotional "heart"; shoulders round your ears makes you *feel* less confident because you are less secure when your centre of gravity is raised.

Etc etc.

I think one further problem that needs mentioning though, is whether you care about yourself enough to use those little techniques. The last few years, I've often known my body was in a mess, making me feel bad because it affected my mood when I was tense etc etc, and I didn't really care. Thought: so what? it hardly matters that I'm in a crap state right now, when most of my life has been crap and relaxing and smiling wont change that. That, as i said before, theres a big part of me that appears to be permanently damaged.

So the problem is: putting a plaster on a wound doesn't stop the scar. And once the scar is there, its permanent.

Note: if you see me being too much intellectual/theoretical, you can tell me!