The Collaborative International Dictionary of English v.0.48:
Brainsick \Brain"sick`\, a. Disordered in the understanding; giddy; thoughtless. -- Brain"sick*ness, n. [1913 Webster]WordNet (r) 3.0 (2006):
brainsick adj 1: affected with madness or insanity; "a man who had gone mad" [syn: brainsick, crazy, demented, disturbed, mad, sick, unbalanced, unhinged]