Insomnia (or sleeplessness) is most often defined by an individual’s report of sleeping difficulties. 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 persistent difficulty falling asleep and/or staying asleep or sleep of poor quality. Insomnia is typically followed by functional impairment while awake. One definition of insomnia is difficulties initiating and/or maintaining sleep, or nonrestorative sleep, associated with impairments of daytime functioning or marked distress for more than 1 month.”
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. 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.
Types of insomnia
Insomnia can be classified as transient, acute, or chronic.
- Transient insomnia lasts for less than a week. It can be caused by another disorder, by changes in the sleep environment, by the timing of sleep, severe depression, or by stress. Its consequences – sleepiness and impaired psychomotor performance – are similar to those of sleep deprivation.
- Acute insomnia is the inability to consistently sleep well for a period of less than a month.
- Chronic insomnia lasts for longer than a month. It can be caused by another disorder, or it can be a primary disorder. Its effects can vary according to its causes. They might include muscular fatigue, hallucinations, and/or mental fatigue. Some people that live with this disorder see things as if they are happening in slow motion, wherein moving objects seem to blend together. Can cause double vision.