I just asked my office-mate: “Addled; is that a word? I just wrote ‘my addled brain,’ is that the right usage?” He replied, “Yes.”
F12 to the dictionary:

addle |ˈadl|
verb [ trans. ] chiefly humorous

make unable to think clearly; confuse : being in love must have addled your brain.
adjective archaic
(of an egg) rotten.

ORIGIN Middle English : from Old English adela [liquid filth,] of Germanic origin; related to Dutch aal and German Adel ‘mire, puddle.’

Oh, how God smiles.