insomnia

Signs and symptoms

Symptoms of insomnia:

Difficulty falling asleep, including difficulty finding a comfortable sleeping position

Waking during the night, being unable to return to sleep, and waking up early

Not able to focus on daily tasks, difficulty in remembering

Daytime sleepiness, irritability, depression or anxiety

Feeling tired or having low energy during the day

Trouble concentrating

Being irritable, acting aggressive, or impulsive

Memory impairment

Sleep onset insomnia is difficulty falling asleep at the beginning of the night, often a symptom of anxiety disorders. Delayed sleep phase disorder can be misdiagnosed as insomnia, as sleep onset is delayed much later than normal, while awakening spills over into daylight hours.

It is common for people who have difficulty falling asleep to also have nocturnal awakenings with difficulty returning to sleep. Two-thirds of these people wake up in the middle of the night, with more than half having trouble falling back to sleep after a middle-of-the-night awakening.

Early morning awakening occurs earlier (more than 30 minutes) than desired, with an inability to go back to sleep and before total sleep time reaches 6.5 hours. Early morning awakening is often a characteristic of depression. Anxiety symptoms may well lead to insomnia. Some of these symptoms include psychological stress, compulsive worrying about the future, feeling overstimulated, and overanalyzing past events.

Chronic insomnia may take a mental toll, affecting social interactions, work, and lifestyle.

Poor sleep quality

Poor sleep quality can occur as a result of, for example, restless legs, sleep apnea, or major depression. Poor sleep quality is defined as the individual not reaching stage 3 or delta sleep, which has restorative properties.

Major depression leads to alterations in the function of the hypothalamic–pituitary–adrenal axis, causing excessive release of cortisol, which can lead to poor sleep quality.

Nocturnal polyuria, excessive night-time urination, can also result in a poor quality of sleep.

Subjectivity

Sleep state misperception is a condition where people believe that they have been awake all night even though sleep tests prove that they have slept for hours. Also called paradoxical insomnia or subjective insomnia, paradoxical insomnia may affect only about 5% of people with insomnia.

Despite sleeping for multiple hours each night and typically not experiencing significant daytime sleepiness or other symptoms of sleep loss, patients feel like they have not slept very much, if at all. They incorrectly believe it takes them an abnormally long time to fall asleep, and they underestimate how long they stay asleep.

Causes

While insomnia can be caused by many conditions, it can also occur without any identifiable cause. This is known as Primary Insomnia. Primary Insomnia may also have an initial identifiable cause but continues after the cause is no longer present. For example, a bout of insomnia may be triggered by a stressful work or life event. However, the condition may continue after the stressful event has been resolved. In such cases, the insomnia is usually perpetuated by the anxiety or fear caused by the sleeplessness itself, rather than any external factors.

Symptoms of insomnia can be caused by or associated with:

Sleep breathing disorders, such as sleep apnea or upper airway resistance syndrome

Use of psychoactive drugs (such as stimulants), including certain medications, herbs, caffeine, nicotine, cocaine, amphetamines, methylphenidate, aripiprazole, MDMA, modafinil, or excessive alcohol intake

Use of or withdrawal from alcohol and other sedatives, such as anti-anxiety and sleep drugs like benzodiazepines

Use of or withdrawal from pain-relievers such as opioids

Heart disease

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 of which the sleeper is unaware

Pain: an injury or condition that causes pain can preclude an individual from finding a comfortable position in which to fall asleep, and can also cause awakening.

Hormone shifts such as those that precede menstruation and those during perimenopause and menopause

Genetics

Heritability estimates of insomnia vary between 38% in males to 59% in females. A genome-wide association study (GWAS) identified 3 genomic loci and 7 genes that influence the risk of insomnia and showed that insomnia is highly polygenic. In particular, a strong positive association was observed for the MEIS1 gene in both males and females. This study showed that the genetic architecture of insomnia strongly overlaps with psychiatric disorders and metabolic traits.

It has been hypothesized that epigenetics might also influence insomnia through a controlling process of both sleep regulation and brain-stress response, having an impact as well on brain plasticity.

Substance-induced

Alcohol is often used as a form of self-treatment for insomnia to induce sleep. However, alcohol use to induce sleep can be a cause of insomnia. Long-term use of alcohol is associated with a decrease in NREM stage 3 and 4 sleep as well as suppression of REM sleep and REM sleep fragmentation. Frequent moving between sleep stages occurs with awakenings due to headaches, the need to urinate, dehydration, and excessive sweating. Glutamine rebound also plays a role when someone is drinking; alcohol inhibits glutamine, one of the body's natural stimulants. When the person stops drinking, the body tries to make up for lost time by producing more glutamine than it needs.

The increase in glutamine levels stimulates the brain while the drinker is trying to sleep, keeping them from reaching the deepest levels of sleep. Stopping chronic alcohol use can also lead to severe insomnia with vivid dreams. During withdrawal, REM sleep is typically exaggerated as part of a rebound effect.

Some people experience sleep disruption or anxiety if they consume caffeine. Doses as low as 100 mg/day, such as a 6 oz (170 g) cup of coffee or two to three 12 oz (340 g) servings of caffeinated soft-drink, may continue to cause sleep disruption, among other intolerances. Non-regular caffeine users have the least caffeine tolerance for sleep disruption. Some coffee drinkers develop tolerance to its undesired sleep-disrupting effects, but others apparently do not.

Like alcohol, benzodiazepines, such as alprazolam, clonazepam, lorazepam, and diazepam, are commonly used to treat insomnia in the short-term (both prescribed and self-medicated), but worsen sleep in the long-term. While benzodiazepines can put people to sleep (i.e., inhibit NREM stage 1 and 2 sleep), while asleep, the drugs disrupt sleep architecture: decreasing sleep time, delaying time to REM sleep, and decreasing deep slow-wave sleep (the most restorative part of sleep for both energy and mood).

Opioid medications such as hydrocodone, oxycodone, and morphine are used for insomnia that is associated with pain due to their analgesic properties and hypnotic effects. Opioids can fragment sleep and decrease REM and stage 2 sleep. By producing analgesia and sedation, opioids may be appropriate in carefully selected patients with pain-associated insomnia. However, dependence on opioids can lead to long-term sleep disturbances.

Risk factors

Insomnia affects people of all age groups, but people in the following groups have a higher chance of acquiring insomnia:

Individuals older than 60

History of mental health disorders, including depression, etc.

Emotional stress

Working late-night shifts

Traveling through different time zones

Having chronic diseases such as diabetes, kidney disease, lung disease, Alzheimer's, or heart disease

Alcohol or drug use disorders

Gastrointestinal reflux disease

Heavy smoking

Work stress

Individuals of low socioeconomic status

Urban neighborhoods

Household stress

Mechanism

Two main models exist regarding the mechanism of insomnia: cognitive and physiological. The cognitive model suggests that rumination and hyperarousal contribute to preventing a person from falling asleep and might lead to an episode of insomnia.

The physiological model is based upon three major findings in people with insomnia; firstly, increased urinary cortisol and catecholamines have been found suggesting increased activity of the HPA axis and arousal; second, increased global cerebral glucose utilization during wakefulness and NREM sleep in people with insomnia; and lastly, increased full body metabolism and heart rate in those with insomnia. All these findings taken together suggest a deregulation of the arousal system, cognitive system, and HPA axis, all contributing to insomnia. However, it is unknown if the hyperarousal is a result of, or cause of insomnia. Altered levels of the inhibitory neurotransmitter GABA have been found, but the results have been inconsistent, and the implications of altered levels of such a ubiquitous neurotransmitter are unknown. Studies on whether insomnia is driven by circadian control over sleep or a wake-dependent process have shown inconsistent results, but some literature suggests a deregulation of the circadian rhythm based on core temperature. Increased beta activity and decreased delta wave activity has been observed on electroencephalograms; however, the implication of this is unknown.

Around half of post-menopausal women experience sleep disturbances, and generally, sleep disturbance is about twice as common in women as men; this appears to be due in part, but not completely, to changes in hormone levels, especially in post-menopause.

Changes in sex hormones in both men and women as they age may account in part for an increased prevalence of sleep disorders in older people.

Diagnosis

In medicine, insomnia is measured using the Athens Insomnia Scale (AIS). It measures eight parameters related to sleep, represented as an overall scale which assesses an individual's sleep quality. It has excellent internal consistency and re-test reliability. The Athens Insomnia Scale for Non-Clinical Populations (AIS-NCA) has been developed and validated in English, Chinese, and German to identify subclinical manifestations of insomnia in a language simpler than the Athens Insomnia Scale and more suitable for self-report. It uses four items to assess sleep problems and three items to assess impaired daytime functioning.

A medical history and a physical examination can identify other conditions that could be the cause of insomnia. A comprehensive sleep history should include sleep habits and sleep environment, medications (prescription and non-prescription, including supplements), alcohol, nicotine, and caffeine intake, and co-morbid illnesses. A sleep diary can be used to track time to bed, total sleep time, time to sleep onset, number of awakenings, use of medications, time of awakening, and subjective feelings in the morning. The sleep diary can be replaced or validated by the use of out-patient actigraphy for a week or more, using a non-invasive device that measures movement.

Not everyone who suffers from insomnia should routinely have a polysomnography study to screen for sleep disorders, but it may be indicated for those with risk factors for sleep apnea, including obesity, a thick neck diameter, or fullness of the flesh in the oropharynx. For most people, the test is not needed to make a diagnosis, and insomnia can often be treated by changing their schedule to make time for sufficient sleep and by improving sleep hygiene.

Some patients may need an overnight sleep study in a sleep lab. Such a study will commonly involve assessment tools including a polysomnogram and the multiple sleep latency test. Specialists in sleep medicine are qualified to diagnose disorders according to the ICSD, 81 major sleep disorder diagnostic categories. Patients with some disorders, including delayed sleep phase disorder, are often misdiagnosed with primary insomnia; when a person has trouble getting to sleep and awakening at desired times, but has a normal sleep pattern once asleep, a circadian rhythm disorder is a likely cause.

In many cases, insomnia is co-morbid with another disease, side effects from medications, or a psychological problem. Approximately half of all diagnosed insomnia is related to psychiatric disorders. For those who have depression, "insomnia should be regarded as a co-morbid condition, rather than as a secondary one;" insomnia typically predates psychiatric symptoms. "In fact, it is possible that insomnia represents a significant risk for the development of a subsequent psychiatric disorder." Insomnia occurs in between 60% and 80% of people with depression and can be a side effect of medications that treat depression.

Types

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 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. Hyperarousal can be linked to acute insomnia since it activates the body's fight-or-flight response. When we encounter stress or danger, our bodies naturally become more alert, which can interfere with our capacity to both fall asleep and remain asleep. This heightened state of arousal can be useful in the short term during threatening situations, but if it continues over an extended period, it can result in acute insomnia. 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. Common causes of chronic insomnia include persistent stress, trauma, work schedules, poor sleep habits, medications, and other mental health disorders. When an individual consistently engages in behaviors that disrupt their sleep, such as irregular sleep schedules, spending excessive time awake in bed, or engaging in stimulating activities close to bedtime, it can lead to conditioned wakefulness contributing to chronic insomnia. People with high levels of stress hormones or shifts in the levels of cytokines are more likely than others to have chronic insomnia. Its effects can vary according to its causes. They might include muscular weariness, hallucinations, and/or mental fatigue.

Prevention

Prevention and treatment of insomnia may require a combination of cognitive behavioral therapy, medications, and lifestyle changes.

Among lifestyle practices, going to sleep and waking up at the same time each day can create a steady pattern which may help to prevent insomnia. Avoidance of vigorous exercise and caffeinated drinks a few hours before going to sleep is recommended, while exercise earlier in the day may be beneficial. Other practices to improve sleep hygiene may include:

Avoiding or limiting naps

Treating pain at bedtime

Avoiding large meals, beverages, alcohol, and nicotine before bedtime

Finding soothing ways to relax into sleep, including the use of white noise

Making the bedroom suitable for sleep by keeping it dark, cool, and free of devices, such as clocks, cell phones, or televisions

Maintain regular exercise

Try relaxing activities before sleeping

Reading before sleep should preferably be done in a chair or another room

Management

It is recommended to rule out medical and psychological causes before deciding on the treatment for insomnia. Cognitive behavioral therapy is an effective first-line treatment for chronic insomnia. The beneficial effects, in contrast to those produced by medications, may last well beyond the stopping of therapy.

Medications have been used mainly to reduce symptoms in insomnia of short duration; their role in the management of chronic insomnia remains unclear. Several different types of medications may be used. Many doctors do not recommend relying on prescription sleeping pills for long-term use. These medications are not recommended for more than four or five weeks, although they can be used longer in certain instances. It is also important to identify and treat other medical conditions that may be contributing to insomnia, such as depression, breathing problems, and chronic pain. As of 2022, many people with insomnia were reported as not receiving overall sufficient sleep or treatment for insomnia.

Non-medication based

Non-medication-based strategies have comparable efficacy to hypnotic medication for insomnia, and they may have longer-lasting effects. Hypnotic medication is only recommended for short-term use because dependence with rebound withdrawal effects upon discontinuation or tolerance can develop.

Non-medication-based strategies provide long-lasting improvements to insomnia and are recommended as a first-line and long-term strategy of management. Behavioral sleep medicine offers non-medication strategies to address chronic insomnia including sleep hygiene, stimulus control, behavioral interventions, sleep-restriction therapy, paradoxical intention, patient education, and relaxation therapy. Some examples are keeping a journal, restricting the time spent awake in bed, practicing relaxation techniques, and maintaining a regular sleep schedule and a wake-up time. Behavioral therapy can assist a patient in developing new sleep behaviors to improve sleep quality and consolidation. Behavioral therapy may include learning healthy sleep habits to promote sleep relaxation, undergoing light therapy to regulate the circadian rhythm, and regulating the circadian clock.

Music may improve insomnia in adults (see music and sleep). EEG biofeedback has demonstrated effectiveness in the treatment of insomnia with improvements in duration as well as the quality of sleep. Self-help therapy (defined as a psychological therapy that can be worked through on one's own) may improve sleep quality for adults with insomnia to a small or moderate degree.

Stimulus control therapy is a treatment for patients who have conditioned themselves to associate the bed or sleep in general with a negative response. As stimulus control therapy involves taking steps to control the sleep environment, it is sometimes referred to interchangeably with the concept of sleep hygiene. Examples of such environmental modifications include using the bed for sleep and sex only, not for activities such as reading or watching television; waking up at the same time every morning, including on weekends; going to bed only when sleepy and when there is a high likelihood that sleep will occur; leaving the bed and beginning an activity in another location if sleep does not occur in a reasonably brief period after getting into bed (commonly ~20 min); reducing the subjective effort and energy expended trying to fall asleep; avoiding exposure to bright light during night-time hours, and eliminating daytime naps.

Medications

Many people with insomnia use sleeping tablets and other sedatives. In some places, medications are prescribed in over 95% of cases. They, however, are a second line treatment. In 2019, the US Food and Drug Administration (FDA) stated it is going to require warnings for eszopiclone, zaleplon, and zolpidem, due to concerns about serious injuries resulting from abnormal sleep behaviors, including sleepwalking or driving a vehicle while asleep.

The percentage of adults using a prescription sleep aid increases with age. During 2005–2010, about 4% of US adults aged 20 and over reported that they took prescription sleep aids in the past 30 days. Rates of use were lowest among the youngest age group (those aged 20–39) at about 2%, increased to 6% among those aged 50–59, and reached 7% among those aged 80 and over. More adult women (5%) reported using prescription sleep aids than adult men (3%). Non-Hispanic white adults reported higher use of sleep aids (5%) than non-Hispanic black (3%) and Mexican-American (2%) adults. No difference was shown between non-Hispanic black adults and Mexican-American adults in use of prescription sleep aids.

As an alternative to taking prescription drugs, some evidence shows that an average person seeking short-term help may find relief by taking over-the-counter antihistamines such as diphenhydramine or doxylamine. Diphenhydramine and doxylamine are widely used in nonprescription sleep aids. They are the most effective over-the-counter sedatives currently available, at least in much of Europe, Canada, Australia, and the United States, and are more sedating than some prescription hypnotics. Antihistamine effectiveness for sleep may decrease over time, and anticholinergic side-effects (such as dry mouth) may also be a drawback with these particular drugs. While addiction does not seem to be an issue with this class of drugs, they can induce dependence and rebound effects upon abrupt cessation of use. However, people whose insomnia is caused by restless legs syndrome may have worsened symptoms with antihistamines.

While insomnia is a common symptom of depression, antidepressants are effective for treating sleep problems whether or not they are associated with depression. While all antidepressants help regulate sleep, some antidepressants, such as amitriptyline, doxepin, mirtazapine, trazodone, and trimipramine, can have an immediate sedative effect and are prescribed to treat insomnia. Trazodone was at the beginning of the 2020s the most prescribed drug for sleep in the United States despite not being indicated for sleep.

Alternative medicine

Herbal products, such as valerian, kava, chamomile, and lavender, have been used to treat insomnia. However, there is no quality evidence that they are effective and safe. The same is true for cannabis and cannabinoids.

Acupuncture is often promoted for insomnia, but evidence for its effectiveness is mixed. It is unclear whether acupuncture is helpful for treating insomnia in the general population. In people with cancer, acupuncture may reduce insomnia severity and improve sleep quality, though its effects are often similar to those of sham acupuncture. While acupuncture can help alleviate insomnia and enhance sleep, it is generally less effective than cognitive behavioural therapy for insomnia (CBT-I).

Prognosis

A survey of 1.1 million residents in the United States found that those who reported sleeping about 7 hours per night had the lowest rates of mortality, whereas those who slept for fewer than 6 hours or more than 8 hours had higher mortality rates. Severe insomnia—sleeping less than 3.5 hours in women and 4.5 hours in men—is associated with a 15% increase in mortality, while getting 8.5 or more hours of sleep per night was associated with a 15% higher mortality rate.

With this technique, it is difficult to distinguish the lack of sleep caused by a disorder, which is also a cause of premature death, versus a disorder that causes a lack of sleep, and the lack of sleep, causing premature death. Most of the increase in mortality from severe insomnia was discounted after controlling for associated disorders. After controlling for sleep duration and insomnia, the use of sleeping pills was also found to be associated with an increased mortality rate.

The lowest mortality was seen in individuals who slept between six and a half and seven and a half hours nightly. Even sleeping only 4.5 hours per night is associated with a very small increase in mortality. Thus, mild to moderate insomnia for most people is associated with increased longevity, and severe insomnia is associated only with a very small effect on mortality. It is unclear why sleeping longer than 7.5 hours is associated with excess mortality.

Epidemiology

Between 10% and 30% of adults have insomnia at any given point in time and up to half of people have insomnia in a given year, making it the most common sleep disorder. About 6% of people have insomnia that is not due to another problem and lasts for more than a month. People over the age of 65 are affected more often than younger people. Females are more often affected than males. Insomnia is 40% more common in women than in men.

There are higher rates of insomnia reported among university students compared to the general population.

Society and culture

The word insomnia is from Latin: in + somnus "without sleep" and -ia as a nominalizing suffix.

The popular press have published stories about people who supposedly never sleep, such as that of Thái Ngọc and Al Herpin. Horne writes "everybody sleeps and needs to do so", and generally this appears true. However, he also relates from contemporary accounts the case of Paul Kern, who was shot in 1915 fighting in World War I and then "never slept again" until he died in 1955. Kern appears to be a completely isolated, unique case.

A culture-bound syndrome is an illness or condition closely associated with particular cultural contexts, suggesting that cultural and societal influences can shape the experience of illness. Biomedicine relies substantially on patients’ self-reports for the clinical diagnosis of insomnia. Although sleeplessness has been acknowledged throughout history, the current prevalence of insomnia has been linked to the industrialisation of modern societies, during which cultural expectations around work, earning money, and the use of time also changed. A more holistic anthropological approach can complement biomedical accounts of insomnia by examining how social, cultural, economic, and environmental conditions shape the experiences and causes of sleep and sleeplessness. Comparing pre-industrialised and industrialised cultures can provide insight into the relationship between industrialisation and sleep, such as the development of artificial light, changing shift patterns, shortened sleep windows, and devices; however, such comparisons alone may be insufficient to explain how these diverse factors operate independently and together in shaping experiences of insomnia.

These cultural influences also extend to how insomnia is classified and diaganosed. Studies show that the distinction between insomnia as a diagnosis and insomnia as a symptom of another condition is often unclear in biomedical research, despite this differentiation being considered important . Anthropologically, this suggests that the prevalence and diagnosis of insomnia can be influenced by how symptoms are classified and interpreted, rather than by quantitative measures alone. One study found that white individuals were more likely to achieve recommended hours of sleep while still being more likely to report nighttime insomnia symptoms. An anthropological study of Human African Trypanosomiasis, or sleeping sickness, similarly found that affected individuals could experience daytime drowsiness and nighttime insomnia while still achieving recommended amounts of sleep. Symptoms were identified not only by when and for how long people slept, but also through behaviour while awake and self or community reporting. This demonstrates that quantified sleep duration alone may not fully capture experiences of insomnia. Biomedical research may interpret differences in prevalence through categories such as gender and race despite these categories being socially and culturally constructed . An anthropological approach instead recognises diagnosis as both a “physical and a cultural act”, allowing broader social and cultural factors to be considered alongside biomedical measures.