Description

Difficulty initiating or maintaining sleep or nonrestorative sleep despite adequate opportunity and circumstances for sleep, resulting in at least one of the following forms of daytime impairment:

• Fatigue or malaise
• Attention, concentration, or memory impairment
• Social or vocational dysfunction or poor school performance
• Mood disturbance or irritability
• Daytime sleepiness
• Motivation, energy, or initiative reduction
• Proneness for errors or accidents at work or while driving
• Tension, headaches, or GI symptoms in response to sleep loss
• Concerns or worries about sleep

Epidemiology

• Predominant age: increases with age
• Predominant sex: female > male (5:1)

Prevalence

• Insomnia (transient and chronic): 5–35% of the population; 10–15% associated with daytime impairment
• Chronic insomnia: 10% middle-aged adults; 1/3 of people aged >65 years

Etiology and Pathophysiology

• Transient/intermittent (<30 days) and short-term (<3 months)
  • Usually caused by an identifiable stressor
  • Stressor can be:
    • Physical (e.g., medical illness, high altitude)
    • Psychological (e.g., stress, excitement, bereavement)
    • Psychosocial (e.g., work deadlines, housing insecurity)
    • Interpersonal (e.g., arguments)
• Usually resolves when stressor is removed
• Chronic (>3 months)
  • Usually not due to one single cause
  • Possible contributing factors:
    • Medical (e.g., gastroesophageal reflux disease, sleep apnea, chronic pain)
    • Psychiatric (e.g., mood, anxiety, psychotic disorders)
    • Primary sleep disorder (e.g., idiopathic, psychophysiologic [heightened arousal and learned sleep-preventing associations], paradoxical [sleep state misperception])
    • Circadian rhythm disorder (e.g., irregular pattern, jet lag, delayed/advanced sleep phase, shift work)
    • Environmental (e.g., lights, noises, movements [partner/young children/pets])
    • Behavioral (e.g., poor sleep hygiene, adjustment sleep disorder)
    • Substance induced
    • Medications (e.g., antihypertensives, antidepressants, corticosteroids, levodopa-carbidopa, phenytoin, quinidine, theophylline, thyroid hormones)

Genetics
No known factors

Risk Factors

• Age
• Female gender
• Medical comorbidities
• Unemployment
• Psychiatric illness
• Impaired social relationships
• Shift work
• Separation from spouse or partner
• Drug and substance abuse
• Family or personal history of insomnia

General Prevention

• Practice consistent sleep hygiene:
  • Fixed wake-up times and bedtimes regardless of amount of sleep obtained (weekdays and weekends)
  • Avoid naps. Go to bed only when sleepy.
  • Sleep in a cool, dark, quiet environment.
  • No activities in bedroom associated with anything but sleep or sex
  • 30-minute wind-down time before sleep
  • If unable to sleep within 20 minutes, move to another environment and engage in quiet activity until sleepy.
• Limit caffeine intake to mornings.
• No alcohol after 4 PM
• Fixed eating times
• Avoid medications that interfere with sleep.
• Regular moderate exercise

Commonly Associated Conditions

• Psychiatric disorders
• Painful musculoskeletal conditions
• Obstructive sleep apnea
• Restless leg syndrome
• Drug or alcohol addiction/dependence