People with dementia in medieval times were often described as childlike, foolish or out of control of their own senses. Around this time, the word ‘dementia’ had started to be used, Anglicised from the Latin. People with the condition were considered unable to differentiate right from wrong; a concern was that by forgetting what they had done in life, a person’s journey to Heaven or Hell might be delayed.

Neurological conditions, as with most diseases, were not understood and were therefore explained through religion. In the 13th century, miracle doctor Roger Bacon agreed that dementia was a natural part of ageing, but less helpfully added that it was a punishment from God for original sin. All over the world, people displaying symptoms of dementia, such as a change in personality or aggression, were diagnosed with being possessed by an evil spirit. This was not a beneficial diagnosis, as these people faced being exorcised, locked away or even killed.

In some parts of the world this is still the case to this day.