Insomnia is the most common sleep disorder, affecting 30-35% of adults transiently and 6-10% chronically. It is defined as difficulty initiating sleep, maintaining sleep, or early morning awakening despite adequate opportunity for sleep, with daytime impairment.

Alarm clock on bedside table indicating sleepless night — Insomnia is the most common sleep disorder, characterized by difficulty falling asleep, staying asleep, or waking too early. Source: Unsplash.

Types of Insomnia

Insomnia is classified by duration. Acute insomnia lasts less than 3 months and is usually triggered by a specific stressor (illness, work stress, travel, emotional upset). It resolves when the trigger resolves and affects 15-20% of adults annually. Chronic insomnia persists for 3 months or longer, occurring at least 3 nights per week. It affects 6-10% of adults. Chronic insomnia may be primary (no identifiable cause) or secondary to another condition. It can also be classified by onset difficulty: sleep-onset insomnia (difficulty falling asleep), sleep-maintenance insomnia (frequent or prolonged awakenings), or early morning awakening (terminal insomnia, common in depression).

Diagnostic Criteria

The DSM-5 criteria for insomnia disorder require: dissatisfaction with sleep quantity or quality (difficulty initiating sleep, maintaining sleep, or early morning awakening), clinically significant distress or impairment in functioning (fatigue, mood disturbance, cognitive impairment, impaired performance), occurring at least 3 nights per week for at least 3 months, despite adequate opportunity for sleep, and not better explained by another sleep disorder (sleep apnea, restless legs syndrome), medical condition, medication, or substance use.

Risk Factors and Causes

Insomnia has multiple contributing factors. Predisposing factors include female sex (1.3-1.6 times more common in women), older age, family history of insomnia (genetic component), and personality traits (anxiety-prone, high neuroticism, perfectionism). Precipitating factors include acute stress (work, relationship, financial), medical illness (pain, respiratory, cardiac, endocrine), psychiatric conditions (depression, anxiety, PTSD), medications (stimulants, antidepressants, decongestants, corticosteroids), substance use (caffeine, alcohol, nicotine), and shift work or time zone changes. Perpetuating factors include maladaptive coping behaviors (extended time in bed, daytime napping, irregular schedule), conditioned arousal (bedroom associated with wakefulness), sleep-related anxiety (worry about not sleeping), and poor sleep hygiene.

Insomnia is driven by predisposing, precipitating, and perpetuating factors, with maladaptive behaviors often maintaining the condition. Source: Unsplash.

⚠ Clinical Correlation

The 3P model (predisposing, precipitating, perpetuating) guides clinical understanding of chronic insomnia. Predisposing factors create vulnerability (genetics, personality). Precipitating factors trigger the initial episode (stress, illness). Perpetuating factors maintain insomnia after the trigger resolves — these are the most important targets for treatment. The most common perpetuating factors: spending too much time in bed trying to “catch up” on sleep (paradoxically worsens sleep efficiency), irregular sleep schedule on weekends, napping, clock watching, and engaging in non-sleep activities in bed (worrying, planning, watching TV). CBT-I specifically targets these perpetuating factors. Without addressing perpetuating factors, acute insomnia often becomes chronic.

Consequences of Chronic Insomnia

Chronic insomnia impairs daytime function more severely than sleep restriction in healthy individuals. Consequences include fatigue and low energy, impaired attention, concentration, and memory, decreased work and academic performance, increased absenteeism, mood disturbance (irritability, depression, anxiety), increased risk of developing major depression (2-3 fold increase), increased risk of hypertension, cardiovascular disease, and type 2 diabetes, increased healthcare utilization and costs, and reduced quality of life comparable to chronic medical conditions.

Cognitive Behavioral Therapy for Insomnia

CBT-I is the first-line treatment for chronic insomnia and is more effective and durable than sleep medications. It combines several components.

Stimulus control strengthens the association between the bed/bedroom and sleep. Instructions: go to bed only when sleepy; use the bed only for sleep and sex; if unable to fall asleep within 20-30 minutes, get out of bed and return only when sleepy; get up at the same time every day regardless of sleep duration; no napping during the day.

Sleep restriction therapy increases homeostatic sleep drive by limiting time in bed to match actual sleep time. Initially, time in bed is restricted to the average total sleep time (minimum 5-5.5 hours). Patients must adhere to the prescribed window and a fixed wake time. As sleep efficiency improves (time asleep divided by time in bed), time in bed is gradually increased by 15-30 minutes. This is the most powerful CBT-I component but requires motivation — it causes initial sleepiness.

Cognitive therapy addresses dysfunctional beliefs about sleep. Common unhelpful beliefs include: “I must get 8 hours of sleep or I will fall apart,” “I have a chemical imbalance that prevents sleep,” “No matter what I do, I will not sleep well,” “The consequences of poor sleep will ruin my life.” These are challenged through Socratic questioning and behavioral experiments.

Sleep hygiene education addresses behaviors that interfere with sleep (caffeine, alcohol, exercise timing, bedroom environment). (Covered in detail in the Sleep Hygiene tutorial.)

Relaxation techniques reduce physiological and cognitive arousal. Examples: progressive muscle relaxation (systematically tense and relax muscle groups), diaphragmatic breathing (slow, deep belly breaths), guided imagery (visualizing a calm, peaceful scene), and mindfulness meditation (observing thoughts and sensations without judgment).

ⓘ Information

CBT-I produces clinically significant improvement in 70-80% of patients with chronic insomnia. Sleep onset latency decreases by 30-60%, wake after sleep onset decreases by 30-50%, and sleep efficiency increases to 80-85% or higher. Improvements are maintained at 6-12 month and 2-year follow-up — unlike medications, whose benefits stop when the drug is discontinued. CBT-I delivered by a trained therapist is most effective, but digital/app-based CBT-I programs show promising results (Sleepio, CBT-I Coach, SHUTi). Four to eight sessions are typical. The first session is the longest (60-90 minutes, including sleep history and treatment planning). Follow-up sessions are 30 minutes. The primary barrier to CBT-I is access to trained providers — digital programs help bridge this gap.

Pharmacotherapy for Insomnia

Medication is appropriate for acute insomnia (< 3 months) or as an adjunct to CBT-I in selected cases. All sleep medications should be used at the lowest effective dose for the shortest duration.

Z-drugs (zolpidem, eszopiclone, zaleplon) are non-benzodiazepine hypnotics that promote sleep onset. They have fewer next-day effects than older agents but still carry risks of tolerance, dependence, and complex sleep behaviors (sleepwalking, sleep eating, sleep driving — especially with zolpidem). Use for 2-4 weeks maximum.

Benzodiazepines (temazepam, triazolam, lorazepam) are effective for sleep but carry higher risks of tolerance, dependence, cognitive impairment, and falls (especially in older adults). They are generally avoided as first-line therapy.

Melatonin receptor agonists (ramelteon) target MT1/MT2 receptors in the SCN. They improve sleep onset without abuse potential and are safe for long-term use. They do not improve sleep maintenance — they are primarily for sleep-onset insomnia.

Orexin receptor antagonists (suvorexant, daridorexant) block the wake-promoting orexin system. They improve both sleep onset and maintenance without significant abuse potential. Next-day sedation is the most common side effect.

Sedating antidepressants (trazodone 25-100 mg, mirtazapine 7.5-15 mg, doxepin 3-6 mg) are commonly used off-label for insomnia, especially when depression or anxiety is comorbid. They improve sleep maintenance but carry risks of next-day sedation, anticholinergic effects, and weight gain (mirtazapine).

Melatonin (0.5-5 mg, 1-2 hours before bed) is a dietary supplement that may help with circadian rhythm disorders and sleep onset but is generally less effective than behavioral interventions for primary insomnia. Higher doses (5-10 mg) are not more effective and may cause morning grogginess.

Treatment Algorithm

First-line treatment for chronic insomnia is CBT-I (stimulus control + sleep restriction + cognitive therapy + sleep hygiene). Medication may be considered for patients who do not respond to CBT-I, cannot access CBT-I, or need short-term relief during the initial phase of CBT-I (when sleep restriction causes sleepiness). For acute insomnia (< 3 months) or situational insomnia (before travel, exam, surgery), short-term hypnotic use (3-7 days) is appropriate. Non-pharmacologic interventions (CBT-I) should be offered before or concurrent with medication.

Summary

Insomnia affects 6-10% of adults chronically. Diagnosis requires difficulty falling or staying asleep with daytime impairment for 3+ months. The 3P model (predisposing, precipitating, perpetuating) guides understanding. CBT-I is the first-line treatment, combining stimulus control, sleep restriction, cognitive therapy, and sleep hygiene. Pharmacotherapy (Z-drugs, orexin antagonists, sedating antidepressants) is appropriate for acute insomnia or as CBT-I adjunct. CBT-I is more effective long-term than medication.