Paranoia
Collier's New Encyclopedia (1921)
a mental disease of the psychosis type, characterized by marked delusions, tending toward persecutory ideas and apt to terminate in a form of mental degeneration. The progressive psychosis may begin almost from childhood, with a systematizing of one or several hallucinations, the symptoms of which are indicated in extravagance of speech or eccentricity of conduct, and easily aroused emotions. An element is the hereditary or acquired predisposition, though physical injury may be a predisposing cause. The paranoiac is usually a person of fixed ideas, who is not amenable to outside influences, but whose persistence in a wrong line of conduct springs from emotional conditions that will not yield to rational exposition. The patient is apt to show himself unduly sensitive and suspicious, to imagine conspiracies directed against him, and to show an indisposition to mingle with others. The effects of these ideas and impulses are shown in the patients' inability to get on in the world, a preference for solitary pursuits, and a dislike for systework in any field except in that matic which leaves them at liberty to indulge in their ideas and delusions. The personal delusion may sometimes take a social or patriotic or religious form, and may display itself in an extreme fervor for which there is no rational basis. Where the hallucinations are strongly developed the paranoiac is apt to show distinct homicidal tendencies. In such cases the only remedy is the removal of the patient to surroundings where he can do no harm, and to improve his condition by such diversions and discipline as may suit his individual case.
What Has Changed in the Last Century
When Collier's wrote this in 1921, "paranoia" was a diagnosis in its own right, understood as a progressive disease ending in "mental degeneration" and treated chiefly by removing the patient to "surroundings where he can do no harm." That unitary disease has since been broken up: modern manuals distinguish delusional disorder (persistent delusions without broader breakdown of thought), paranoid personality disorder, and psychosis arising in schizophrenia — and DSM-5 in 2013 abolished even the "paranoid schizophrenia" subtype as unreliable. Confinement and "diversions and discipline" gave way to drug treatment after chlorpromazine's introduction in the 1950s, now combined with psychological therapy. The 1921 claim that strongly developed cases are "apt to show distinct homicidal tendencies" is the part modern clinicians reject most firmly; most people with paranoid delusions are never violent, and the older hereditary-degeneration framing has gone with it.
Written for this edition, 2026.