Definition and Diagnosis
Insomnia Disorder involves persistent difficulty initiating or maintaining sleep, or early morning awakening with an inability to return to sleep, occurring at least three nights a week for three months or more, along with associated daytime impairment.
Epidemiology
Chronic insomnia affects roughly 10% of adults, with transient insomnia symptoms being far more common. Prevalence increases with age and is higher among women and individuals with co-occurring medical or psychiatric conditions.
Risk Factors
Risk factors include a history of anxiety or depression, chronic stress, irregular sleep schedules, certain medications, and other sleep disorders such as sleep apnea. A tendency toward heightened physiological arousal ("hyperarousal") is also implicated.
Symptoms and Subtypes
Symptoms include difficulty falling asleep, frequent nighttime awakenings, waking too early, and non-restorative sleep, along with daytime fatigue, mood disturbance, and impaired concentration. Many individuals also develop anxiety specifically about sleep itself.
Diagnosis
Diagnosis is based on sleep history, sleep diaries, and DSM-5-TR criteria, with additional testing such as polysomnography reserved for suspected co-occurring sleep disorders. Clinicians distinguish primary insomnia from insomnia secondary to another medical or psychiatric condition.
Treatment
Cognitive Behavioral Therapy for Insomnia (CBT-I) is the first-line, evidence-based treatment, focusing on sleep restriction, stimulus control, and addressing unhelpful beliefs about sleep. Medications may be used short-term, but are generally not recommended as a long-term standalone solution.
Prognosis
Many individuals achieve significant improvement with CBT-I, often with lasting benefits after treatment ends. Untreated chronic insomnia is associated with increased risk of mood and anxiety disorders and reduced quality of life.
Reference
American Academy of Sleep Medicine. (2023). <i>International Classification of Sleep Disorders</i> (3rd ed., text rev.).