Insomnia: Causes, Consequences, and Treatment
Insomnia disorder is defined by dissatisfaction with sleep quality or quantity (difficulty falling asleep, staying asleep, or early morning awakening) occurring at least 3 nights per week for at least 3 months, causing daytime impairment. Acute insomnia (lasting days to weeks) is a near-universal human experience in response to stress, travel, illness, or life change. Chronic insomnia (3+ months) affects approximately 10-15% of adults and involves a distinct perpetuating cycle that separates it from normal transient sleep difficulty: “hyperarousal” — a persistent state of elevated physiological and cognitive arousal that interferes with sleep onset and maintenance regardless of the original precipitating cause.
The perpetuating factors of chronic insomnia are well-characterized and the basis of CBT-I treatment: (1) Excessive time in bed (“sleep opportunity extension”) — spending 10 hours in bed to get 6 hours sleep paradoxically fragments sleep further and dilutes sleep pressure; (2) Conditioned arousal — if bed is associated with wakefulness, frustration, and anxiety rather than sleep, the bedroom environment becomes a conditional stimulus for wakefulness; (3) Catastrophizing thoughts about sleep and its consequences — which activate the HPA axis stress response and prevent sleep initiation; (4) Daytime behavioral consequences of poor sleep (excessive napping, reduced activity, avoided social engagements) that reduce daytime alertness and sleep drive.
CBT-I is the first-line recommended treatment for chronic insomnia per American Academy of Sleep Medicine guidelines, with a 70-80% response rate and effects that persist at 12-month follow-up (vs sedative-hypnotics that work only while taken and cause rebound insomnia on discontinuation). The core CBT-I components: (1) Sleep restriction — temporarily limiting time in bed to actual sleep time to build intense sleep pressure, then gradually extending as sleep efficiency improves; (2) Stimulus control — going to bed only when sleepy, getting out of bed after 20 minutes if not asleep, and reserving the bed for sleep and sex only; (3) Cognitive restructuring of catastrophic sleep thoughts; (4) Sleep hygiene (consistent timing, cool dark room, no screens 1-2 hours before bed); (5) Relaxation training.
Pharmacological insomnia treatment: benzodiazepines and Z-drugs (zolpidem, eszopiclone, zaleplon) are effective for acute insomnia but are not recommended for chronic use due to tolerance development, dependence, cognitive impairment (particularly in older adults), falls risk, and rebound insomnia on discontinuation. They do not treat the underlying hyperarousal — they suppress symptoms. For older adults specifically, they are listed on the Beers Criteria as inappropriate medications due to cognitive impairment, fall, and fracture risks. Melatonin (1-5mg taken 1-2 hours before desired sleep time) is effective for circadian rhythm disorders (jet lag, delayed sleep phase) but less effective for sleep maintenance insomnia. Doxepin at low doses (3-6mg) and suvorexant (orexin receptor antagonist) have evidence for sleep maintenance with better safety profiles than benzodiazepines.