Insomnia (or sleeplessness) is an individual's report of sleeping difficulties.
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 occur at any age, but it is particularly common in the elderly.
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. Insomnia is present when there is difficulty initiating or maintaining sleep or when the sleep that is obtained is non-refreshing or of poor quality. These problems occur despite adequate opportunity and circumstances for sleep and they must result in problems with daytime function.Acute insomnia is also known as short term insomnia or stress related insomnia.
Chronic insomnia lasts for longer than a month. It can be caused by another disorder, or it can be a primary disorder. People with high levels of stress hormones or shifts in the levels of cytokines are more likely to have chronic insomnia. 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. Chronic insomnia can cause double vision.
Symptoms and comorbidities
Symptoms of insomnia can be caused by or can be co-morbid with:
Use of psychoactive drugs (such as stimulants), including certain medications, herbs, caffeine, nicotine, cocaine, amphetamines, methylphenidate, aripiprazole, MDMA, modafinil, or excessive alcohol intake.
Withdrawal from depressant drugs such as opioids and benzodiazepines.
Use of fluoroquinolone antibiotic drugs, see fluoroquinolone toxicity, associated with more severe and chronic types of insomnia.
Restless Legs Syndrome, which can cause sleep onset insomnia due to the discomforting sensations felt and the need to move the legs or other body parts to relieve these sensations.
Periodic limb movement disorder (PLMD), which occurs during sleep and can cause arousals that the sleeper is unaware of.
Pain ,an injury or condition that causes pain can preclude an individual from finding a comfortable position in which to fall asleep, and can in addition cause awakening.
Hormone shifts such as those that precede menstruation and those during menopause
Life events such as fear, stress, anxiety, emotional or mental tension, work problems, financial stress, birth of a child and bereavement.
Mental disorders such as bipolar disorder, clinical depression, generalized anxiety disorder, post traumatic stress disorder, schizophrenia, obsessive compulsive disorder, dementia, or ADHD.
Disturbances of the circadian rhythm, such as shift work and jet lag, can cause an inability to sleep at some times of the day and excessive sleepiness at other times of the day. Chronic circadian rhythm disorders are characterized by similar symptoms.
Certain neurological disorders, brain lesions, or a history of traumatic brain injury
Medical conditions such as hyperthyroidism and rheumatoid arthritis.
Abuse of over-the counter or prescription sleep aids (sedative or depressant drugs) can produce rebound insomnia.
Poor sleep hygiene, e.g., noise.
Parasomnias, which include such disruptive sleep events as nightmares, sleepwalking, night terrors, violent behavior while sleeping, and REM behavior disorder, in which the physical body moves in response to events within dreams
A rare genetic condition can cause a prion-based, permanent and eventually fatal form of insomnia called fatal familial insomnia.
Physical exercise. Exercise-induced insomnia is common in athletes, causing prolonged sleep onset latency.
Sleep studies using polysomnography have suggested that people who have sleep disruption have elevated nighttime levels of circulating cortisol and adrenocorticotropic hormone They also have an elevated metabolic rate, which does not occur in people who do not have insomnia but whose sleep is intentionally disrupted during a sleep study. Studies of brain metabolism using positron emission tomography (PET) scans indicate that people with insomnia have higher metabolic rates by night and by day. The question remains whether these changes are the causes or consequences of long-term insomnia.
A common misperception is that the amount of sleep required decreases as a person ages. The ability to sleep for long periods, rather than the need for sleep, appears to be lost as people get older. Some elderly insomniacs toss and turn in bed and occasionally fall off the bed at night, diminishing the amount of sleep they receive.
It is important to identify or rule out medical and psychological causes before deciding on the treatment for insomnia. Attention to sleep hygiene is an important first line treatment strategy and should be tried before any pharmacological approach is considered. Pharmacological treatments have been used mainly to reduce symptoms in acute insomnia; their role in the management of chronic insomnia remains unclear.