Things You Didn't Know About Hitler That Will Blow Your Mind

From theorising that "madness" could be cured by simulating a near-death experience by drowning, to the still widely used electric shock therapy, the logic of these treatments have more rational and hopeful intentions than you might think.

Lunatic asylums have gone out of fashion — but many were only closed in the last few decades.

So why were they thought to be a good idea in the first place and what has replaced them?

Professor Scull, who wrote Madness in Civilisation, said the popular view in ancient cultures was that madness was caused by evil spirits.

In the Bible's Old Testament, or the Jewish Torah, evil spirits and divine punishment were considered causes of mental disorders.

"It is true even in Islamic societies and in Chinese society for example, those beliefs in possession and spirits and some kind of punishment are very widespread," Professor Scull said.

The Ancient Greeks had a more natural approach to mental illness and associated it more closely with physical sickness.

"Illness as a whole is explained in terms of the four humours, so blood, black bile, yellow bile, phlegm," Professor Scull said.

"The relative balance of those things affect one's temperament, one's character, and if they are sufficiently out of balance will tip you over into melancholia or into mania."

Despite this slightly more scientific view, superstitious views about spirits and demons persisted, especially within the Christian texts.

"Jesus on a number of occasions is portrayed as casting demons out and devils out of bodies. He is supposed to have cast as many as five devils out of Mary Magdalene," Professor Scull said.

"So that issue of maybe exorcising madness becomes something that from Christ passes to his disciples, and then to bishops and even ordinary priests. That's one way in which Christianity for example becomes associated with this issue."

Medieval times were littered with the idea that Christians, especially saints' and martyrs' remains and relics, could cure followers.

"Obviously in Chaucer's Canterbury tales, [it] is about pilgrims going to Canterbury to be cured of various kinds of illness — bodily illness but also mental distress," Professor Scull said.

He said the Arab world persevered with early scientific understandings fostered by the Greeks and Romans, while western cultures stagnated.