Description

• Difficulty initiating or maintaining sleep or nonrestorative sleep despite adequate opportunity and circumstances for sleep
• Causes at least one of the following forms of daytime impairment related to nighttime sleep difficulty:
  • 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

• Most common sleep disorder
• 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 >65 years

Etiology and Pathophysiology

• Transient/intermittent (<30 days) and short-term (<3 months)
  • Usually caused by an identifiable stressor
    • Stress/excitement/bereavement
    • Shift work
    • Medical illness
    • High altitude
  • Can lead to chronic insomnia
• Chronic (>3 months)
  • Usually not due to one single cause
  • Medical: gastroesophageal reflux disease, sleep apnea, chronic pain, congestive heart failure, Alzheimer disease, Parkinson disease, chronic fatigue syndrome, irritable bowel syndrome
  • Psychiatric: mood, anxiety, psychotic disorders
  • Primary sleep disorder: idiopathic, psychophysiologic (heightened arousal and learned sleep-preventing associations), paradoxical (sleep state misperception)
  • Circadian rhythm disorder: irregular pattern, jet lag, delayed/advanced sleep phase, shift work
  • Environmental: light (liquid crystal display [LCD] clocks), noise (snoring, household, traffic), movements (partner/young children/pets)
  • Behavioral: poor sleep hygiene, adjustment sleep disorder
  • Substance induced
  • Medications: antihypertensives, antidepressants, corticosteroids, levodopa-carbidopa, phenytoin, quinidine, theophylline, thyroid hormones

Risk Factors

• Age
• Female gender
• Medical comorbidities
• Unemployment
• Psychiatric illness
• Impaired social relationships
• Lower socioeconomic status
• 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)
  • Go to bed only when sleepy.
  • Avoid naps.
  • Sleep in a cool, dark, quiet environment.
  • No activities or stimuli 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 (>4 hours prior to bedtime)

Commonly Associated Conditions

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