Hello, Tumnus! You raise what I feel is an important question: "Why do elevated moods sometimes trigger depressed moods in some percentage of depressives?" I have had similar experiences. One day or hour I will experience as much excitement as my meds will let me, and then the next day or hour I'll "pay for it" with low mood, again, as low as my meds will allow.

I speculate this may have something to do with brain chemistry. Our moods and emotions affect and are affected by what's percolating in the old grey matter. It may be that in the aftermath of "excitement" the chemical mix returns to "normal" (normal for us) and we experience withdrawal, which manifests as increased depression. I don't know.

Tumnus, I'm sorry you experience this. You're not alone.