I think a lot of the problem is that "we" don't know much yet about brain chemicals and how they work and/or the effects of heart, head, and body on all that too. One can think one's self different and we know if we eat (chemical technically) better/differently that has effects and exercising, emotions, etc.

My asthma gets better/worse often when there's nothing I can see happening differently but stress/anxiety seems to fluctuate a bit too closely to it to get me to say there's nothing to either the asthma reacting to the stress or versa vice! :-)

I think when I'm thinking bad thoughts, I'd have to say my head is keeping me down and when I'm feeling bad, my emotions? The other night (in the middle thereof :-) I recognied I was anxious/agitated for no reason and things that I don't normally even see, much less are bothered by, were bothering me and making me more anxious. I saw dust above the door on the frame there and you'd think I was in my death bed and sure no one would come to comfort me before I went! My present and future filth and decay flashed before my eyes and that was all there was; no love, hope, pleasure, cleanliness, godliness, etc. All the good stuff was swept away.

But, one thing I have going for me now is I recognize such states as "not real"/not important (?) and can wait them out. I imagine it's like seeing hallucinations and knowing they're hallucinations. If it hadn't been the middle of the night I might have gotten up and cleaned the dust off the door frame (it's still there, I'd forgotten it again until just now) and that would have comforted me a tiny bit (but something else would have taken its place. That whole day I was on edge and little things were bothering me but it took "dust" on a door frame I don't normally even notice to cue me that the whole antsy thing was not "normal."

Short answer? I'd say it's my feelings/emotions that cause me the most trouble because my head more often has a grip on reality. Sure I can take a leap of faith with my emotions and override my head occasionally but it's usually my feelings that try to keep me stuck?