Insomnia Disorder

Insomnia disorder is the dissatisfaction with sleep quantity or quality with complaints of difficulty initiating or maintaining sleep. These sleep complaints cause clinically significant distress and/or impairment in social, occupational, or other areas of functioning. The sleep disturbance can occur during the course of an other mental disorder or medical condition, or it may occur independently.

  • Insomnia disorder involves daytime impairments (fatigue and daytime sleepiness) as well as nighttime sleep difficulties (this is more common among older individuals, chronic pain, and sleep apnea)
  • Cognitive impairment includes difficulties with attention, concentration, and memory (even with performing simple tasks)
  • Mood changes include irritability, mood lability, and less commonly as depressive or anxiety symptoms
  • Insomnia disorder is the most prevalent of all sleep disorders
  • About 30% of the general population have insomnia symptoms and 10% have an associated functional daytime impairment, about up to 10% have symptoms that meet criteria for insomnia disorder.
Risk Factors
  • Older age, women (more prevalent among females than males), widowed, lower socioeconomic status, smokers, drinkers, and with co-morbid psychiatric and medical conditions. Disrupted sleep and insomnia also have a familial disposition. Insomnia is higher in monozygotic twins compared to dizygotic twins; it is also higher in first-degree family members.
  • Poor sleep hygiene, irregular sleep scheduling, and the fear of not sleeping also exacerbate symptoms
  • Noise, light, uncomfortably high or low temperature, and high altitude may also increase vulnerability to insomnia.
Criterion A

A predominant complaint of dissatisfaction with sleep quantity or quality, associated with 1 (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 returning to sleep without caregiver intervention
  3. Early-morning awakening with inability to return to sleep.
Criterion B

The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioural, or other important areas of functioning.

Criterion C

The sleep difficulty occurs at least 3 nights per week.

Criterion D

The sleep difficulty is present for at least 3 months.

Criterion E

The sleep difficulty occurs despite adequate opportunity for sleep.

Criterion F

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).

Criterion G

The insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication).

Criterion H

Coexisting mental disorders and medical conditions do not adequately explain the pre-dominant complaint of insomnia.



Specify if:

  • With non-sleep disorder mental comorbidity, including substance use disorders
  • With other medical comorbidity
  • With other sleep disorder

Duration Specifier

Specify if:

  • Episodic: Symptoms last at least 1 month but less than 3 months.
  • Persistent: Symptoms last 3 months or longer.
  • Recurrent: Two (or more) episodes within the space of 1 year.

Types of Insomnia

Types of Insomnia

Type Description
Sleep-onset insomnia (initial insomnia) Difficulty initiating sleep at bedtime. Defined by a subjective sleep latency greater than 20-30 minutes.
Sleep maintenance insomnia (middle insomnia) Frequent or prolonged awakenings throughout the night. Defined by subjective time awake after sleep onset greater than 20-30 minutes
Late insomnia Early-morning awakening with an inability to return to sleep.
Early-morning awakening Awakening at least 30 minutes before the scheduled time and before total sleep time reaches 6.5 hours.
Non-restorative sleep Poor sleep quality that does not leave the individual rested upon awakening despite adequate duration. This is a common sleep complaint usually occurring in association with difficulty initiating or maintaining sleep, or less frequently in isolation.

The onset of insomnia symptoms can occur at any time during life, but the first episode is more common in young adulthood. Less frequently, insomnia begins in childhood or adolescence. Insomnia disorder is considered to be due to hyper-arousal during the day (all-day hyper-vigilance) with difficulty initiating/maintaining sleep during the night. There are several models that attempt to explain insomnia, including: (1) the Cognitive model, (2) the Physiologic model, and (3) the Neuroendocrine model.

Insomnia can also be situational, persistent, or recurrent. Situational or acute insomnia usually lasts a few days or a few weeks and is often associated with life events or rapid changes in sleep schedules or environment. It usually resolves once the initial precipitating event subsides.

History and Physical

A detailed evaluation is important to understand the cause and nature of the insomnia, this includes:

  • Physical examination
  • Past and present psychiatric history
  • Medication use
  • Alcohol, drug, and caffeine use
  • Sleeping habits
  • Sleep partner’s report
  • Questionnaires and sleep diary


Measuring sleep quality can be done through scales, questionnaires, and sleep diaries:

Measurement Scales for Sleep Quality

Epworth Sleepiness Scale (ESS)
Rater Patient
Description The ESS is a self-administered questionnaire with 8 questions.
Download ESS Information
Insomnia Severity Index (ISI)
Rater Patient
Description The ISI has seven questions rated on a scale of 0 to 4.[1]
Download ISI Download
Pittsburgh Sleep Quality Index (PSQI)
Rater Patient
Description The PSQI is an effective instrument used to measure the quality and patterns of sleep in adults. It differentiates “poor” from “good” sleep quality by measuring 7 components.
Download PSQI Download
Name Rater Description Download
Epworth Sleepiness Scale (ESS) Patient The ESS is a self-administered questionnaire with 8 questions. ESS Information
Insomnia Severity Index (ISI) Patient The ISI has seven questions rated on a scale of 0 to 4.[2] ISI Download
Pittsburgh Sleep Quality Index (PSQI) Patient The PSQI is an effective instrument used to measure the quality and patterns of sleep in adults. It differentiates “poor” from “good” sleep quality by measuring 7 components. PSQI Download


Polysomnography usually shows impairments of sleep continuity (e.g., increased sleep latency and time awake after sleep onset and decreased sleep efficiency (percentage of time in bed asleep) and may show increased stage 1 sleep and decreased stages 3 and 4 sleep. The severity of these sleep impairments does not always match the individual's clinical presentation or subjective complaint of poor sleep, as individuals with insomnia often underestimate sleep duration and overestimate wakefulness relative to polysomnography.

Quantitative electroencephalographic (EEG) analyses may indicate that individuals with insomnia have greater high-frequency EEG power relative to good sleepers both around the sleep onset period and during non-rapid eye movement sleep, a feature suggestive of increased cortical arousal. Individuals with insomnia disorder may have a lower sleep propensity and typically do not show increased daytime sleepiness on objective sleep laboratory measures compared with individuals without sleep disorders.

Physiologic Markers

Other laboratory measures show evidence, although not consistently, of increased arousal and a generalized activation of the hypothalamic-pituitary-adrenal axis (e.g., in creased cortisol levels, heart rate variability, reactivity to stress, metabolic rate). In general, findings are consistent with the hypothesis that increased physiological and cognitive arousal plays a significant role in insomnia disorder.


Psychological treatment of insomnia disorder includes sleep hygiene, cognitive behavioural therapy, stimulus control, bed restriction, and relaxation techniques. With the advent of the internet, many of these therapies have become widely accessible online (see table below).

This table is not an endorsement of the therapies, but rather a sampling of what is available online.

Online Insomnia Therapies

Name Description Cost
CBT for Insomnia 5-session on-line cognitive behavioural therapy (CBT) program for insomnia. $24.95 US to $49.95 US
CBT-i Coach Structured program that teaches strategies to improve sleep and help alleviate symptoms of insomnia. Free
Sleepio Evidence-based CBT-I online and mobile app program $300 US for a 12-month subscription
SlumberPRO Self-help program from Queensland Australia, requires 30-60 minutes each day and program lasts 4-8 weeks $39 AUS
Go! To Sleep 6-week CBT-I program (and mobile app) available through Cleveland Clinic of Wellness $3.99 US for app, or $40 US for web
SHUTi 6-week CBT-I program, evaluated in 2 randomized trials involving adults with insomnia and cancer survivors $135 US for 16 weeks access, or $156 US for 20 weeks access
Restore CBT-I A 6-week CBT-I program evaluated in a randomized trial £99 to £199
Sleep Training System 6-week on-line CBT-I program with money-back guarantee and personalized feedback $29.95 US


Based on American Academy of Sleep Medicine Guidelines[3] and College of Physicians and Surgeons of Alberta Guidlines.[4]

Pharmacological Treatment of Insomnia

1st Line Benzodiazepine-receptor agonists: Temazepam (US FDA Approval: Estazolam, flurazepam, quazepam, triazolam*)
Non-Benzodiazepine-receptor agonists: Zopiclone, zolpidem, eszopiclone, zaleplon
2nd Line Sedating antidepressants: Trazodone, doxepin, mirtazapine and other sedating SSRIs
Off-label Antipsychotics: Olanzapine, quetiapine and risperidone are used in clinical practice
Supplements: Melatonin, tryptophan and valerian root
Anticonvulsants: Gabapentin, pregabalin

Don't forget!

Short-term hypnotic treatment should always be supplemented with behavioural and cognitive therapies if possible.

Clinical Pearls

  • Although triazolam is FDA-approved for insomnia disorder, it should really not be used given its short half-life and therefore high potential for addiction and misuse.
  • When using antipsychotics, you must consider the following: weight gain and therefore worsening of apnea, increased leg restlessness, hyperlipidemia, glucose dysregulation, and QT prolongation. All these reasons should make you think twice about prescribing antipsychotics for sleep. For this reason alone, the NIH Chronic insomnia panel states: “all (antipsychotics) agents have significant risks, and thus their use in the treatment of chronic insomnia cannot be recommended”