We don’t really understand sleep beyond knowing that not getting enough of it can kill you.

We don’t really understand sleep beyond knowing that not getting enough of it is bad for you. To be a bit more accurate, it might be better to say that we understand a lot about the physiology of sleep, but very little about what it’s for. We know quite a lot, for example, about the reticular activating system, which helps keep us awake, and the locus coeruleus, which helps regulate when we get tired. We know about the different kinds of brain activity that can be observed during the different stages of sleep and we know enough for there to be disagreement as to how many stage of sleep we think there are. The part that we know embarrassingly little about is what sleep actually does and why we need it. We know what happens if you don’t get it: rapid cognitive impairment, loss of coordination, impaired memory, depression, hallucination, and generally a very bad day. Contrary to what you might learn from watching old episodes of Star Trek, generally speaking, it isn’t possible for an ordinary person to die of sleep deprivation. Even in extreme cases, as of people who are being forcibly kept awake as a means of torture, lack of sleep will increase your mortality from many other medical problems but the body will eventually pass out and sleep long before sleep loss becomes physically dangerous in and of itself. However, as with almost everything in medicine – and in the world, in my experience – there are exceptions to that.

There’s a very, very, very rare disease – rare to the point of approaching one in a billion – called fatal familial insomnia, or FFI. FFI is a disorder of the brain which, like the famous mad cow disease, is caused by the production of misfolded protein produced within the body (we don’t know if this means that the disease is transmissible the same way as bovine spongiform encephalitis, or the more common human prion disorder, Creutzfeldt-Jakob disease, because fortunately no one with FFI has ever been cannibalized by another human being, to our knowledge). All known cases of FFI to date, going back over three hundred years, have apparently been genetic and run in affected families. People with FFI experience a disruption in their sleep cycles, such that they slowly lose the ability to transition from light sleep to deep sleep. Sleep becomes non-restful, and many of the body’s hormonal regulation and self-repair systems, which are activated during sleep, stop working properly.

Although the gene for FFI is present from birth, most people who carry it begin to develop symptoms only around midlife, and evolves from mild to lethal over the course of one to two years. Initially, the person begins to have worsening difficulty initiating sleep, leading to exhaustion and mostly psychiatric effects, particularly mood problems worsening anxiety which, after four to six months, evolve into full on hallucinations. As the body’s ability to maintain homeostasis becomes impaired, people develop fevers, tremors, and difficulty speaking. Pulse and blood pressure rise. The gut becomes constipated. Pupils may become contracted and double vision often develops as the muscles around the eyes weaken. Appetite becomes poor in addition to the swallowing muscles losing coordination. In most cases, the disease progresses to a complete inability to sleep within one year, quickly followed by dementia and death. Altogether, FFI illustrates what happens if someone were to really, truly be incapable of sleeping: rapid erosion of mental health followed by progressive collapse of the body’s systems and death.

As with so many diseases, while this sort of illness is rare almost to the point of non-existence in reality, it’s something that could easily happen in a campaign. A disease similar to FFI almost wiped out the crew of the Enterprise D, a surgically-induced form gave psychic powers to Tony Todd on the X-Files, and by virtue of the fact that magic doesn’t have to make sense, it’s the sort of thing that might happen to a group of PCs at any time. Could an angry Vistani afflict a character with a curse whose long-term effects surprise even the caster? What happens if an evil bard devises a reversed form of sleep or deep slumber? What happens if the spell is made permanent? Could a symbol of wakefulness be surreptitiously cast on a character’s bedroll, slowly driving them insane in the days to weeks it takes to deduce what’s happening? And what happens if someone is the target of a nightmare spell every night for two weeks? FFI illustrates this is one instance where, if anything, the game mechanics probably don’t portray just how horrific the real consequences of such effects might be. 

More than four years ago, Dr. Eris Lis, M.D., began writing a series of brilliant and informative posts on RPGs through the eyes of a medical professional, and this is the one that appeared here on April 4, 2015. Lis is a physician, gamer, and author of the Skirmisher Publishing LLC OGL sourcebook Insults & Injuries, which is also available for the Pathfinder RPG system.