Overall, Prichard defined insanity as a, "chronic disease, manifested by deviations from the healthy and natural state of the mind." He then proposed four broad categories. Moral insanity was for disorders that only seemed to arise from a person's feelings and habits, not his intellect. The other three types involved increasing degrees of intellectual abnormality: a partial derangement that was limited to certain trains of thought; a full mania, by which was meant 'raving madness' regardless of topic; and lastly, a breakdown of any connections between ideas, referred to as incoherence or dementia.