Peculiarity

Whereever singularity of natural temper is strikingly obvious, there exists a connate predisposition to insanity: this may be difficult of explanation, but it is reasonable to conclude that where such peculiarities exist, analogous states of the organs of intellect are present. These causes may arise from a certain structure of the primary moving powers of the nervous system, as where it results from hereditary taint; or be occassioned by the frequent or continued agency of causes tending to produce such peculiarity, such as habitual intoxication, protracted lucubrations, or the inordinate indulgence of any passion.

C***
Practical Observations on Insanity, p. 24.