NICE1 suggest that ‘The prevalence of delirium in people on medical wards in hospital is about 20% to 30%, and 10% to 50% of people having surgery develop delirium’, but they also indicate that the ‘reporting of delirium is poor in the UK’. A psychiatrist friend estimates that half the people staying overnight in hospitals will have delirium.
Numerous studies draw attention to a connection between delirium and increased risk of morbidity and mortality (illness and death).
It can result from almost any physical, psychological or indeed pharmaceutical disturbance you can think of, but this project will focus primarily on adult people who experience delirium whilst receiving an unusually high level of care in hospitals – in the area known variously as critical care, intensive treatment, intensive therapy, intensive care (ITU, ICU, A(adult)ICU etc). A great introduction to the phenomenon in critical care can be found here. In the 40s, Karl Bonhoeffer drew a distinction between delirium caused by external factors and that experienced by people with long-term disorders. Whether this remains the prevailing view today, I don’t know.
These delirious episodes are related to ‘ITU psychosis’ – although only some people who are delirious will have psychotic symptoms. It is also problematic to use the disingenuously neat word ‘episode’, for reasons I will come to later. It’s worth pointing out that hallucinations can involve taste, smell and touch – as much as sight.
Robert Hughes described it thus:
“Some of my coma dreams were fairly hellish…Crewing on a pearling lugger… I had been captured by pirates and found myself bound, chained, and stacked like a piece of cordwood in the hold of a Chinese slaving junk… Something weird had been fixed to my right arm, driven into the flesh, immobilising me. I realised …that it had been surgically implanted by two fiendish Chinese doctors who were not only slave traffickers but Maoist spies…
In reality … a quite non-fiendish and certainly non-Maoist Irish doctor…” 
Paul Robertson says that at one point during his coma he was ‘on a ship full of dead people’ (Hearing Ragas, BBC Radio 4, Sept 2012 – see previous entry).
Oddly enough when I google ‘ship in delirium’ I get a reference to Canadian pleasure craft(?), and then a fictional story of a ship called ‘Delirium’ (‘formerly known as the Sacred Hart’ – http://thedreadfleet.com/). The whole thing could be an engorged metaphor for a complex operation – hinting at a societal fear of artificiality within the body, of a kind of Faustian pact made with medicine. Certainly Paul Robertson’s experience testifies to the Fae being ‘a terrifying bunch’.
Formerly a merchant-pillaging ship known as the Sacred Hart, this vessel was smashed to pieces against the rocks of Avalon in a fierce storm. None of the crew survived the night except for Captain Redcap. Lying injured on the beach, the captain’s last sane moments were spent eyeing the coast of broken wood and bodies, feeling nothing but pain and regret. The next day she awoke and began to wander the island. Upon discovery of a village an extremely welcoming woman by the name of Oaklara bid the struggling captain to a bed where her wounds could be treated.
One day Oaklara approached the captain with a contract, revealing her and the villagers as otherworldly beings of extraordinary power known as Fae. An accord was struck between Redcap and the island’s magical inhabitants; she would eternally serve as the Faerie Courts’ hand in the mortal realm in return for both the resurrection of both her ship and crew, and the immortality which the pact necessitates.
Oaklara walked her to the dock, explaining to Redcap how pieces of her wrecked ship had been integrated into an existing ancient, yet powerful vessel which had been constructed many years ago for the sole purpose of serving the future Agent of the Fae. And what a magnificent ship it was, with beautiful black masts and white sails, ornately designed with brass-tarnished fixtures and the both intricate and not-so inanimate carvings of gargoyles and dragons. Floating just above the water’s surface, great octopus tentacles of extraordinary handiwork were carved into the base of the hull.
As the galleon came further into view, Redcap noticed the horrifying looking creatures lurking about the ship and surrounding dock. Her crew had been revived, but they would never be human again. Even the ship itself was a living monster, assisting the grotesque crew in its own special ways. Ropes and planks would sometimes move about on their own, assisting in the more menial tasks. These creatures of many forms would soon prove to serve as the Delirium’s most powerful weapons. Redcap stared in silent awe at her new galleon of delirium and destruction, as both captain and eternal prisoner of the melancholy vessel.
Nowadays she’s grown quite attached to her newfound position, going so far as to dye the sails red in the blood of Delirium’s enemies. A signal, that all those whom dare cross this ship’s path inevitably will face a quick and bloody end unless there’s a good reason otherwise. The Fae are a terrifying bunch, and to trifle with their agent is suicide.”
(With thanks to ‘The Dread Fleet’)
 NICE clinical guideline 103: Delirium: diagnosis, prevention and management, July 2010
 Things I Didn’t Know, Robert Hughes, Knopf 2006