A state, usually precipitated by drinking and drug use, that approaches catatonia. Although common symptoms are indistinguishable from those of a coma, certain individuals may inexplicably maintain random higher brain functions, such as speech, and sexual ardor. May also be used as an adjective or descriptor.
1. Oh man... stay away from Noodles. He's gone brainstem.
2. That stupid brainstem Billy just tried to grab my boobs!