Full Idea
The sentences 'I feel depressed' and 'I feel exuberant' are related in the way in which 'He runs slowly' and 'He runs swiftly' are related, and not in the way in which 'He has a red book' and 'He has a brown book' are related.
Gist of Idea
'I feel depressed' is more like 'he runs slowly' than like 'he has a red book'
Source
Roderick Chisholm (Person and Object [1976], 1.8)
Book Reference
Chisholm,Roderick: 'Person and Object' [Open Court 1976], p.49
A Reaction
Ducasse 1942 and Chisholm 1957 seem to be the sources of the adverbial theory. I gather Chisholm gave it up late in his career. The adverbial theory seems sort of right, but it doesn't illuminate what is happening.