I agree that the word "disease" is certainly overused these days, there are still some things that should rightfully use the word.

Besides, whether you call them "diseases" or "disorders" or another term, there are many ways that our neurology can fail us. The "Classification" section of this Wikipedia article lists several major ones, but there's countless more:

http://en.wikipedia.org/wiki/Neurological_disorder#Classific...