Insomnia is as common a symptom, just as lack of appetite. Although about 30% of adults have symptoms of insomnia, it is seldom reported, and hence is an under- treated disorder.
This could be due to the fact that sleep, like other basic needs, is taken for granted and therefore due importance is not given to it. This information is surprising because adequate sleep is very essential for an individual to function well. Less than 10% of adults are likely to suffer from chronic insomnia, of which women and elderly are likely to be more susceptible.