Insomnia, or sleeplessness, is an individual’s reported sleeping difficulties. “Insomnia” is derived from the Latin word “Somnus”, the name of the Roman god of sleep, with the incorporation of the prefix “in-” to add contradiction. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions: “Do you experience difficulty sleeping?” or “Do you have difficulty falling or staying asleep?”
Thus, insomnia is most often thought of as both a sign and a symptom that can accompany several sleep, medical, and psychiatric disorders characterized by a persistent difficulty falling asleep and/or staying asleep or sleep of poor quality. Insomnia is typically followed by functional impairment while awake. A definition of insomnia is, “difficulties initiating and/or maintaining sleep, or non-restorative sleep, associated with impairments of daytime functioning or marked distress for more than 1 month.” Insomnia can occur at any age, but it is particularly common in the elderly. Insomnia can be short term (up to three weeks) or long term (above 3-4 weeks), which can lead to memory problems, depression, irritability and an increased risk of heart disease and automobile related accidents.
Insomnia can be grouped into primary and secondary, or comorbid, insomnia. Primary insomnia is a sleep disorder not attributable to a medical, psychiatric, or environmental cause. It is described as a complaint of prolonged sleep onset latency, disturbance of sleep maintenance, or the experience of non-refreshing sleep. A complete diagnosis will differentiate between:
insomnia as secondary to another condition,
primary insomnia co-morbid with one or more conditions, or
free-standing primary insomnia.