The Science of Consciousness:

Chapter 12: Sleep

What this chapter is about: what is sleep?

What is sleep, why do we sleep, and what happens when we don't? How does the brain govern the sleep-wake cycle?


Additional information


Sleep disorders - Insomnia. The most common sleep disorder is almost certainly insomnia, trouble in getting to sleep, maintaining sleep, or waking too early. I am often asked what people can do about it. We all have restless nights occasionally, and although annoying, leaving us tired, and in need of catching up, they are nothing to worry about. However regularl problems with maintaing sleep are  distressing and can have serious effects on mental and physical health. (One of the themes of this book is how closely related these two are.)

Sleep hygiene. I am lucky in rarely having touble sleeping, but even I avoid caffeine after 6 pm, and try to avoid MSG (even if it is a placebo effect). I go to bed and sleep at the same time every night, wake up at the same time every day (inlcuding weekends and Christmas), and don't have a television in the bedoom. I set my iPad to a nice warm night colour, and avoid anything too stimulating. If I had trouble sleeping I would avoid my phone and laptop altogether. You might try avoiding eating too late.

From the shelf and over-the-counter medication. Melatonin might help you; I took it in the good old days when we could go anywhere for reducing jet lag. It isn't widely avaliable in the UK, but you can get it online (and just from the shelf in the USA). It is available on prescription. I'm not sure why it's not widely available because over-the-counter alternatives include first-generation antihistamines such as chlorpheniramine and diphenydramine, and these have been associated with with an increased risk of cognitive impairment in older individuals. It should be said that these are largely correlational studies and as yet the association is far from definite. When I have time I will add some references but they're easily found in a search engine.

Prescription only. There are now several drugs available that facilitate sleep. They're much safer than the older barbituates, although the widely prescribed benzodiazepines are not recommended for any period of time because they can be addictive.

Long-term treatment. If you have persistent insomnia you need to find out why. Is there an underlying health condition? If so, insist on investigation in addition to medication. Is there something about your lifestyle that hinders sleep? Are you getting enough exercise? Are you sleeping too much? Are you having a long afternoon nap? Remember that there is a wide variation in how much sleep people need.


In the news

Sleepwalking man cleared of sexually assaulting woman. "A man with a history of sleepwalking has been found not guilty by reason of insanity of sexually assaulting his friend's girlfriend."


Additional review questions

Would a conscious robot need to sleep?