Insomnia Disorder

Prevalence

  • Population-based estimates indicate that about:

    1. One-third of adults report insomnia symptoms.

    2. 10%-15% experience associated daytime impairments.

    3. 6%-10% have symptoms that meet criteria for insomnia disorder.


  • Insomnia disorder is the most prevalent of all sleep disorders.

  • Insomnia is a more prevalent complaint among females than among males, with a gender ratio of about 1.44:1.

  • Although insomnia can be a symptom or an independent disorder, it is most frequently observed as a co-morbid condition with another medical condition or mental disorder.

Risk factors

Temperamental

  • Anxiety or worry-prone personality or cognitive styles.

  • Increased arousal predisposition.

  • Tendency to repress emotions.

Environmental

  • Stress.

Sleep disturbances are more likely to occur when predisposed individuals are exposed to precipitating events, such as major life events (e.g., illness, separation) or less severe but more chronic daily stress.

  • Perpetuating factors.

Perpetuating factors (e.g., poor sleep habits, irregular sleep scheduling, fear of not sleeping) feed into the insomnia problem and may contribute to a vicious cycle that may induce persistent insomnia.

  • Noise.

  • Light.

  • Uncomfortably high or low temperature.

  • High altitude.

Genetic and physiological

  • Female gender and advancing age are associated with increased vulnerability to insomnia.

  • Disrupted sleep and insomnia display a familial disposition. The extent to which this link is inherited through a genetic predisposition remains undetermined.

Course modifiers

Deleterious course modifiers include poor sleep hygiene practices (e.g., excessive caffeine use, irregular sleep schedules).

Symptoms

  • A predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms:

1. Difficulty initiating sleep.

In children, this may manifest as difficulty initiating sleep without caregiver intervention.

2. Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings.

In children, this may manifest as difficulty initiating sleep without caregiver intervention.

3. Early-morning awakening with 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).