Sleep medicine is a fairly new speciality, having been only properly developed within the last 20 years or so. There are currently 89 sleep disorders on the list of International Classification of Sleep Disorders and this is growing all the time (1). The disorders are divided into three groups: dyssomnias, which can be insomnia or hypersomnia (where people sleep too much); parasomnias, which describe undesired events that occur alongside sleep; and medical and psychiatric disorders that affect sleep.

The main area of interest for new sleep drug development by the pharmaceutical industry is the dyssomnia group. It is estimated that 30-35 per cent of the population suffer from some form of insomnia at any time and the economic consequences are dramatic. Insomniacs seem to have more frequent visits to their doctor for other complaints, they probably suffer low mood, and they lose more days from work. So, in terms of the cost to the nation, insomnia is important.

THE MARKET FOR SLEEP MEDICATION

The low number of prescribed hypnotics and the high number of over-the-counter sleep aids indicate that there is the potential for massive growth in sales of new hypnotics. Pharmaceutical companies have produced and, continue to develop, hypnotics and treatments for insomnia, and alerting medications to combat sleepiness, particularly daytime sleepiness.

However, there are different types of insomnia. Take, for example, transient insomnia. We are all aware that anxiety can bring on insomnia – perhaps if you are worried about the events of the next day. Or you may have insomnia because you’ve drunk too much coffee.