Insomnia is a sleep disorder which can be subdivided into three areas. It is characterized by any of the following:
b) not being able to sleep, even if fatigued,
c) lack of sleeping hours.
Insomnia can be classified into three types based on the length of time it affects an individual.
Transient insomnia lasts less than a week. It is due to changes in living or working conditions. Then there is Short-term insomnia, or acute transient insomnia, which lasts for less than three weeks and has similar origin as transient insomnia.
Finally there is, chronic insomnia which may be classified as primary or secondary:
1) Primary chronic insomnia - not caused by any physical or mental condition. 2) Secondary chronic insomnia