Insomnia

Insomnia

Insomnia, also known as sleeplessness, is a sleep disorder where individuals have trouble sleeping. They may experience difficulty falling asleep, staying asleep as long as desired, or both. Insomnia often leads to daytime sleepiness, low energy, irritability, and a depressed mood. It can increase the risk of motor vehicle collisions and cause problems with focusing and learning. Insomnia may be short-term, lasting for days or weeks, or long-term, lasting more than a month.

Causes

Insomnia world map

Complications of insomnia

Insomnia can occur independently or as a result of another problem. Conditions that can cause insomnia include psychological stress, chronic pain, heart failure, hyperthyroidism, heartburn, Restless Leg Syndrome, menopause, certain medications, and substances such as caffeine, nicotine, and alcohol. Other risk factors include working night shifts and sleep apnea.

Diagnosis

Diagnosis of insomnia is based on sleep habits and an examination to look for underlying causes. A sleep study may be conducted to look for underlying sleep disorders. Screening may be done with two questions: "do you experience difficulty sleeping?" and "do you have difficulty falling or staying asleep?"

Treatment

Sleep hygiene and lifestyle changes are typically the first treatment for insomnia. Sleep hygiene includes a consistent bedtime, exposure to sunlight, a quiet and dark room, and regular exercise. Cognitive behavioral therapy may be added to this. While sleeping pills may help, they are associated with injuries, dementia, and addiction. These medications are not recommended for more than four or five weeks. The effectiveness and safety of alternative medicine is unclear.

Signs and Symptoms

Symptoms of insomnia include:

• Difficulty falling asleep, including difficulty finding a comfortable sleeping position
• Waking during the night, being unable to return to sleep, and waking up early
• Inability to focus on daily tasks and difficulty remembering
• Daytime sleepiness, irritability, depression or anxiety
• Feeling fatigued or having low energy during the day
• Trouble concentrating
• Irritability, acting aggressive or impulsive

Sleep Quality

Poor sleep quality can occur as a result of conditions such as 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.

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. 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, and females are more often affected than males. Descriptions of insomnia date back to ancient Greece. 

Types of Insomnia

Sleep-Onset Insomnia

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 to much later than normal, while awakening spills over into daylight hours.

Nocturnal Awakenings

It is common for patients with insomnia to also have nocturnal awakenings with difficulty returning to sleep. Two-thirds of these patients 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

Early morning awakening is an awakening occurring 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 also lead to insomnia, with symptoms including tension, compulsive worrying about the future, feeling overstimulated, and overanalyzing past events.

Nocturnal Polyuria

Nocturnal polyuria, or excessive nighttime urination, can be very disturbing to sleep and may contribute to insomnia.

Sleep State Misperception

Some cases of insomnia are not truly insomnia in the traditional sense, as people experiencing sleep state misperception often sleep for a normal amount of time. The problem is that, despite sleeping for multiple hours each night and typically not experiencing significant daytime sleepiness or other symptoms of sleep loss, they do not feel like they have slept very much, if at all. Because their perception of their sleep is incomplete, they incorrectly believe it takes them an abnormally long time to fall asleep, and they underestimate how long they remain asleep. 

Causes

Symptoms of insomnia can be caused by or be associated with:

• Use of psychoactive drugs (e.g., stimulants, certain medications, herbs, caffeine, nicotine, cocaine, amphetamines, methylphenidate, aripiprazole, MDMA, modafinil, excessive alcohol intake)
• Use of or withdrawal from alcohol and other sedatives, such as benzodiazepines
• Use of or withdrawal from pain-relievers, such as opioids
• Previous thoracic surgery
• Heart disease
• Deviated nasal septum and nocturnal breathing disorders
• Restless legs syndrome
• Periodic limb movement disorder (PLMD)
• Pain, which can make it difficult to find a comfortable sleeping position
• Hormone shifts, such as those preceding menstruation and those during menopause
• Life events (e.g., fear, stress, anxiety, emotional or mental tension, work problems, financial stress, birth of a child, bereavement)
• Gastrointestinal issues (e.g., heartburn, constipation)
• Mental disorders (e.g., bipolar disorder, clinical depression, generalized anxiety disorder, post-traumatic stress disorder, schizophrenia, obsessive-compulsive disorder, dementia, ADHD)
• Disturbances of the circadian rhythm, such as shift work and jet lag
• Certain neurological disorders, brain lesions, or history of traumatic brain injury
• Medical conditions (e.g., hyperthyroidism, rheumatoid arthritis)
• Abuse of over-the-counter or prescription sleep aids
• Poor sleep hygiene (e.g., noise, excessive caffeine consumption)
• Rare genetic conditions, such as fatal familial insomnia
• Physical exercise, especially in athletes
• Increased exposure to blue light from artificial sources (e.g., phones, computers)
• Chronic pain, lower back pain, and asthma

Sleep studies have suggested that people with sleep disruption have elevated nighttime levels of circulating cortisol and adrenocorticotropic hormone, as well as elevated metabolic rates.

Genetics

Heritability estimates of insomnia range from 38% in males to 59% in females. Genome-wide association studies (GWAS) have identified genomic loci and genes that influence the risk of insomnia, showing a strong overlap with psychiatric disorders and metabolic traits.

Substance-Induced Insomnia

Alcohol-Induced

Alcohol is often used to self-treat insomnia but can also cause it. Long-term use of alcohol is associated with decreased NREM stage 3 and 4 sleep, suppression of REM sleep, and REM sleep fragmentation.

Benzodiazepine-Induced

Benzodiazepines, such as alprazolam, clonazepam, lorazepam, and diazepam, are commonly used to treat insomnia in the short-term but can worsen sleep in the long-term. They can decrease sleep time, delay time to REM sleep, and decrease deep slow-wave sleep.

Opioid-Induced

Opioid medications, such as hydrocodone, oxycodone, and morphine, can be used for insomnia associated with pain due to their analgesic properties and hypnotic effects. However, opioids can fragment sleep and decrease REM and stage 2 sleep, and dependence on opioids can lead to long-term sleep disturbances.

Risk Factors

Insomnia affects people of all age groups, but certain groups have a higher chance of developing insomnia:

• Individuals older than 60
• History of mental health disorders, including depression
• Emotional stress
• Working late-night shifts
• Traveling through different time zones
• Having chronic diseases (e.g., diabetes, kidney disease, lung disease, Alzheimer's, heart disease)
• Alcohol or drug use disorders
• Gastrointestinal reflux disease
• Heavy smoking
• Work stress

Mechanism

Two main models exist for the mechanism of insomnia: (1) cognitive and (2) physiological. The cognitive model suggests rumination and hyperarousal contribute to preventing a person from falling asleep, potentially leading to an episode of insomnia.

The physiological model is based on three major findings in people with insomnia: increased urinary cortisol and catecholamines, increased global cerebral glucose utilization during wakefulness and NREM sleep, and increased full-body metabolism and heart rate. These findings suggest a dysregulation 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.

Diagnosis

A qualified sleep specialist should be consulted for the diagnosis of any sleep disorder. Past medical history and a physical examination need to be done to eliminate other conditions that could cause insomnia. A comprehensive sleep history, sleep diary, and possibly outpatient actigraphy should be considered. Polysomnography might be indicated for patients with additional symptoms, such as sleep apnea, obesity, or high-risk fullness of the flesh in the oropharynx.

In many cases, insomnia is comorbid with another disease, side effects from medications, or a psychological problem. Approximately half of all diagnosed insomnia is related to psychiatric disorders, and in many cases, insomnia should be regarded as a comorbid condition rather than a secondary one. Insomnia can occur in between 60% and 80% of people with depression and may partly be due to the treatment used for depression. 

DSM-5 Criteria

The DSM-5 criteria for insomnia include the following:

• Predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms: a. Difficulty initiating sleep. (In children, this may manifest as difficulty initiating sleep without caregiver intervention.) b. Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings. (In children, this may manifest as difficulty returning to sleep without caregiver intervention.) c. Early-morning awakening with the inability to return to sleep.
• The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning.
• The sleep difficulty occurs at least 3 nights per week.
• The sleep difficulty is present for at least 3 months.
• The sleep difficulty occurs despite adequate opportunity for sleep.
• The insomnia is not better explained by and does not occur exclusively during the course of another sleep-wake disorder (e.g., narcolepsy, a breathing-related sleep disorder, a circadian rhythm sleep-wake disorder, a parasomnia).
• The insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication).
• Coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia.

Types

Insomnia can be classified as transient, acute, or chronic:

1. Transient insomnia: lasts for less than a week; can be caused by another disorder, changes in sleep environment, sleep timing, severe depression, or stress.
2. Acute insomnia: lasts for less than a month; occurs when there is difficulty initiating or maintaining sleep, or when sleep is non-refreshing or poor quality, despite adequate opportunity and circumstances for sleep.
3. Chronic insomnia: lasts for longer than a month; can be caused by another disorder or can be a primary disorder.

Prevention

Prevention and treatment of insomnia may require a combination of cognitive behavioral therapy, medications, and lifestyle changes. Some practices to improve sleep hygiene may include:

• Going to sleep and waking up at the same time each day
• Avoiding vigorous exercise and caffeinated drinks a few hours before going to sleep
• 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
• Sleeping with a positive attitude
• Maintaining regular exercise
• Trying relaxing activities before sleeping
• Using your bed only for sleep or sex
• Stop checking the time

Treatment

Treatment options for insomnia can be divided into non-pharmacological and pharmacological approaches.

Non-pharmacological treatments

• Cognitive Behavioral Therapy for Insomnia (CBT-I): A structured program that helps patients identify and replace thoughts and behaviors that cause or worsen sleep problems with habits that promote sound sleep. Components of CBT-I may include sleep restriction, stimulus control, sleep hygiene education, relaxation training, and cognitive restructuring.
• Relaxation techniques: Techniques such as progressive muscle relaxation, deep breathing exercises, and guided imagery can help reduce anxiety and promote relaxation, making it easier to fall asleep and stay asleep.
• Sleep hygiene education: Providing information about good sleep habits and practices to promote a better sleep environment, such as maintaining a regular sleep schedule, creating a comfortable sleep environment, and avoiding substances that can interfere with sleep.
• Sleep restriction therapy: Limiting the time spent in bed to the actual time spent sleeping, in order to increase sleep efficiency. This approach may involve gradually increasing time in bed as sleep efficiency improves.
• Stimulus control therapy: Helps to re-establish a healthy association between the bed and sleep by setting consistent sleep and wake times, avoiding activities other than sleep and sex in the bedroom, and avoiding watching the clock.

Pharmacological treatments

• Prescription medications: Doctors may prescribe medications such as hypnotics (e.g., zolpidem, eszopiclone, zaleplon), sedating antidepressants (e.g., trazodone, amitriptyline, mirtazapine), or benzodiazepines (e.g., temazepam, lorazepam) for short-term use to help patients fall asleep or stay asleep.
• Over-the-counter (OTC) sleep aids: Some OTC sleep aids contain antihistamines (e.g., diphenhydramine, doxylamine), which can cause drowsiness. However, these may also cause side effects such as daytime drowsiness, dry mouth, and blurred vision.
• Melatonin: Melatonin supplements can help regulate sleep-wake cycles and are particularly useful for individuals with circadian rhythm sleep disorders or those experiencing jet lag.
• Herbal remedies: Some individuals may find relief from insomnia using herbal remedies such as valerian root, chamomile, or lavender. However, the efficacy and safety of these remedies may vary, and it is important to consult a healthcare professional before using them.

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