A certain variety of maniacs

Among the varieties of maniacs met with in medical practice there is one which, though by no means rare, has been little noticed by writers on this subject: I refer to those cases in which the individuals perform most of the common duties of life with propriety, and some of them, indeed, with scrupulous exactness, who exhibit no strongly marked features of either temperament, no traits of superior or defective mental endowment, but yet take violent antipathies, harbour unjust suspicions, indulge strong propensities, affect singularity in dress, gait, and phraseology; are proud, conceited and ostentatious; easily excited and with difficulty appeased; dead to sensibility, delicacy and refinement; obstinately riveted to the most absurd opinions; prone to controversy and yet incapable of reasoning; always the hero of their own tale; using hyperbolic high-flown language to express the most simple ideas, accompanied by unnatural gesticulation, inordinate action, and frequently by the most alarming expression of countenance. On some occasions they suspect sinister intentions on the most trivial grounds, on others are a prey to fear and dread from the most ridiculous and imaginary sources; now embracing every opportunity of exhibiting romantic courage and feats of hardihood, then indulging themselves in all manners of excesses.

Persons of this description, to the casual observer, might appear actuated by a bad heart, but the experienced physician knows it is the head which is defective. They seem as if constantly affected by a greater or less degree of stimulation from intoxicating liquors, while the expression of countenance furnishes an infallible proof of mental disease.

C***
Practical Observations on Insanity, p. 14f.