I sat up with a jerk, after contemplating the wallpaper in the television dramatisation of The Woman in White, when a character wondered aloud if he was paranoid. Paranoid? How could he be? The novel was finished by 1860 and paranoid was not invented till 1902 (in a translation of a book by the psychiatrist Emil Kraepelin) Kraepelin applied paranoid to delusions in what he called dementia praecox. From 1912 dementia praecox began to be supplanted by schizophrenia.

None of this was dreamt of by Wilkie Collins. The TV adaptor, Fiona Seres, would never have introduced references to Tesla cars. On the other hand, she no doubt used invisibly anachronistic turns of phrase. It’s the in-between anachronisms that catch me in the ribs. Collins was interested by a sane person being locked up in a lunatic asylum, ‘the most horrible of all imprisonments’. The BBC publicity used the term mentally ill woman. Interestingly, Collins hardly uses the words mad, mania or lunatic in the novel. He often refers to a mind that’s agitated.

The Woman in White was soon categorised as a sensation novel — one that shocks. Collins often uses sensation for a feeling, good or bad. It’s his atmosphere that alarms. In 1871, Collins and his emulators were satirised in W.S. Gilbert’s play A Sensation Novel. Gilbert plays with the idea of characters who, by a preternatural power, must act out ‘those stock characters of the sensation novelist in roles which are most opposed to their individual tastes’, until they suddenly step out of the fiction, as in Flann O’Brien’s At Swim-Two-Birds (1939).

The Woman in White has a wicked baronet, which Gilbert notes as essential, along with ingredients such as: ‘Linch pin, fallen from a carriage,/ Forged certificate of marriage,/ Money wrongly won at whist,/ Finger of a bigamist,/ Pocket-knife with blood-stained blade,/ Telegram, some weeks delayed.’

As for paranoia, which in ancient Greek meant ‘madness’, it spent 100 years from 1750 in the form paranœa meaning ‘delirium’. The element noia came from nous, which Alexander Pope rhymed with house, as it continued to be, descending in meaning from ‘intellect’ or ‘mind’ to ‘common sense’ or ‘gumption’.