Insanity is a disordered condition of the mind. The ancients considered a loss of mind due to the bewitching influence of Luna, or the Moon, hence the words lunacy and lunatic. Loss of mental power is due to any one of many causes and takes many forms. Insanity may or may not be accompanied by wasting away of the brain, that is to say, a breaking down of cells. Popular names for insanity consisting merely of derangement are melancholy, stupor, hallucination, mania, epilepsy, and hysteria. Melancholy is accompanied by depression; mania by unusual exaltation or similar mental acuteness. A third class of cases is entirely distinct from these mentioned. Weak-mindedness, idiocy, and imbecility are due to an undeveloped brain. We cannot speak of loss of mind in these cases, for the patients have never possessed well ordered minds, but are dull and incapable of other than physical routine.
In other forms of insanity there is a breaking down and wasting away of brain cells. The dementia sometimes noticed in extreme old age is of this sort. Certain grievous diseases bring about the same result. Insanity may be produced by sickness or a disease; it may be the immediate result of a mental shock, such as comes from loss of property, grief, fright, shame, religious enthusiasm, or political excitement. Some people go insane from living too much alone; others keep their minds too active, and are stimulated by overstudy or the excitement of society. The study of the various forms of insanity is one of the profoundest and most difficult subjects of medical inquiry. No reputable physician will claim to have mastered more than one form of insanity.
Modern treatment of insanity differs very greatly from the treatment of the XIX century, and the results are most gratifying. Since the advent of psychoanalysis, which threw a flood of light on the working of the mind, the hope for recovery of demented persons is greater than formerly, even though psychoanalysis is of aid only when the aberration is treated in its incipient stage.
