DSM-IV

In DSM-IV, this disorder is called Primary Insomnia

Diagnostic Criteria

A. The predominant complaint is difficulty initiating or maintaining sleep, or nonrestorative sleep, for at least 1 month.

B. The sleep disturbance (or associated daytime fatigue) causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

C. The sleep disturbance does not occur exclusively during the course of Narcolepsy, Breathing-Related Sleep Disorder, Circadian Rhythm Sleep Disorder, or a Parasomnia.

D. The disturbance does not occur exclusively during the course of another mental disorder (e.g., Major Depressive Disorder, Generalized Anxiety Disorder, a delirium).

E. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.

Differential Diagnosis

Short sleepers

"Normal" sleep duration varies considerably in the general population. Some individuals who require little sleep ("short sleepers") may be concerned about their sleep duration. Short sleepers are distinguished from those with Primary Insomnia by their lack of difficulty falling asleep and by the absence of characteristic symptoms of Primary Insomnia (e.g., intermittent wakefulness, fatigue, concentration problems, or irritability).

Primary Hypersomnia

Daytime sleepiness, which is a characteristic feature of Primary Hypersomnia, can also occur in Primary Insomnia, but is not as severe in Primary Insomnia. When daytime sleepiness is judged to be due to insomnia, an additional diagnosis of Primary Hypersomnia is not given.

Circadian Rhythm Sleep Disorder

Jet Lag and Shift Work Types of Circadian Rhythm Sleep Disorder are distinguished from Primary Insomnia by the history of recent transmeridian travel or shift work. Individuals with the Delayed Sleep Phase Type of Circadian Rhythm Sleep Disorder report sleep-onset insomnia only when they try to sleep at socially normal times, but they do not report difficulty falling asleep or staying asleep when they sleep at their preferred times.

Narcolepsy

Narcolepsy may cause insomnia complaints, particularly in older adults. However, Narcolepsy rarely involves a major complaint of insomnia and is distinguished from Primary Insomnia by symptoms of prominent daytime sleepiness, cataplexy, sleep paralysis, and sleep-related hallucinations.

Breathing-Related Sleep Disorder

A Breathing-Related Sleep Disorder, particularly central sleep apnea, may involve a complaint of chronic insomnia and daytime impairment. A careful history may reveal periodic pauses in breathing during sleep or crescendo-decrescendo breathing (Cheyne-Stokes respiration). A history of central nervous system injury or disease may further suggest a Breathing-Related Sleep Disorder. Polysomnography can confirm the presence of apneic events. Most individuals with Breathing-Related Sleep Disorder have obstructive apnea that can be distinguished from Primary Insomnia by a history of loud snoring, breathing pauses during sleep, and excessive daytime sleepiness.

Parasomnias

Parasomnias are characterized by a complaint of unusual behavior or events during sleep that sometimes may lead to intermittent awakenings. However, it is these behavioral events that dominate the clinical picture in a Parasomnia rather than the insomnia.

Other mental disorders and Insomnia Related to Another Mental Disorder

Primary Insomnia must be distinguished from mental disorders that include insomnia as an essential or associated feature (e.g., Major Depressive Disorder, Generalized Anxiety Disorder, Schizophrenia). The diagnosis of Primary Insomnia is not given if insomnia occurs exclusively during the course of another mental disorder. A thorough investigation for the presence of other mental disorders is essential before considering the diagnosis of Primary Insomnia. A diagnosis of Primary Insomnia can be made in the presence of another current or past mental disorder if the mental disorder is judged to not account for the insomnia or if the insomnia and the mental disorder have an independent course. In contrast, when insomnia occurs as a manifestation of, and exclusively during the course of, another mental disorder (e.g., a Mood, Anxiety, Somatoform, or Psychotic Disorder), the diagnosis of Insomnia Related to Another Mental Disorder may be more appropriate. This diagnosis should only be considered when the insomnia is the predominant complaint and is sufficiently severe to warrant independent clinical attention; otherwise, no separate diagnosis is necessary.

Sleep Disorder Due to a General Medical Condition and Substance-Induced Sleep Disorder

Primary Insomnia must be distinguished from Sleep Disorder Due to a General Medical Condition, Insomnia Type. The diagnosis should be Sleep Disorder Due to a General Medical Condition when the insomnia is judged to be the direct physiological consequence of a specific general medical condition (e.g., pheochromocytoma, hyperthyroidism). This determination is based on history, laboratory findings, or physical examination. Substance-Induced Sleep Disorder, Insomnia Type, is distinguished from Primary Insomnia by the fact that a substance (i.e., a drug of abuse, a medication, or exposure to a toxin) is judged to be etiologically related to the insomnia. For example, insomnia occurring only in the context of heavy coffee consumption would be diagnosed as Caffeine-Induced Sleep Disorder, Insomnia Type, With Onset During Intoxication.

DSM-5

Diagnostic Criteria

A. 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 returning to sleep without caregiver intervention.)
  3. Early-morning awakening with inability to return to sleep.

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

C. The sleep difficulty occurs at least 3 nights per week.

D. The sleep difficulty is present for at least 3 months.

E. The sleep difficulty occurs despite adequate opportunity for sleep.

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).

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

H. Coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia.

Specify if:

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

Note: Record also the relevant associated mental disorder, medical condition, or other sleep disorder immediately after insomnia disorder in order to indicate the association.

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.

Note: Acute and short-term insomnia (i.e., symptoms lasting less than 3 months but otherwise meeting all criteria with regard to frequency, intensity, distress, and/or impairment) should be recorded as an other specified insomnia disorder.

Note: The diagnosis of insomnia disorder is given whether it occurs as an independent condition or is cormorbid with another mental disorder (e.g., major depressive disorder), medical condition (e.g., pain), or another sleep disorder (e.g., a breathing-related sleep disorder). For instance, insomnia may develop its own course with some anxiety and depressive features but in the absence of criteria being met for any one mental disorder. Insomnia may also manifest as a clinical feature of a more predominant mental disorder. Persistent insomnia may even be a risk factor for depression and is a common residual symptom after treatment for this condition. With comorbid insomnia and a mental disorder, treatment may also need to target both conditions. Given these different courses, it is often impossible to establish the precise nature of the relationship between these clinical entities, and this relationship may change over time. Therefore, in the presence of insomnia and a comorbid disorder, it is not necessary to make a casual attribution between the two conditions. Rather, the siagnosis of insomnia disorder is made with concurrent specification of the clinically comorbid conditions. A concurrent insomnia diagnosis should only be considered when the insomnia is sufficiently severe to warrant independent clinical attention; otherwise, no separate diagnosis is necessary.

Differential Diagnosis

Normal sleep variations

Normal sleep varies considerably across individuals. Some individuals who require little sleep ("short sleepers") may be concerned about their sleep duration. Short sleepers differ from individuals with insomnia disorder by the lack of difficulty falling or staying asleep and by the absence of characteristic daytime symptoms (e.g., fatigue, concentration problems, irritability). However, some short sleepers may desire or attempt to sleep for a longer period of time and, by prolonging time in bed, may create an insomnia-like sleep pattern. Clinical insomnia also should be distinguished from normal, age-related sleep changes. Insomnia must also be distinguished from sleep deprivation due to inadequate opportunity or circumstance for sleep resulting, for example, from an emergency or from professional or family obligations forcing the individual to stay awake.

Situational/acute insomnia

Situational/acute insomnia is a condition lasting a few days to a few weeks, often associated with life events or with changes in sleep schedules. These acute or short-term insomnia symptoms may also produce significant distress and interfere with social, personal, and occupational functioning. When such symptoms are frequent enough and meet all other criteria except for the 3-month duration, a diagnosis of other specified insomnia disorder or unspecified insomnia disorder is made.

Delayed sleep phase and shift work types of circadian rhythm sleep-wake disorder

Individuals with the delayed sleep phase type of circadian rhythm sleep-wake disorder report sleep-onset insomnia only when they try to sleep at socially normal times, but they do not report difficulty falling asleep or staying asleep when their bed and rising times are delayed and coincide with their endogenous circadian rhythm. Shift work type differs from insomnia disorder by the history of recent shift work.

Restless legs syndrome

Restless legs syndrome often produces difficulties initiating and maintaining sleep. However, an urge to move the legs and any accompanying unpleasant leg sensations are features that differentiate this disorder from insomnia disorder.

Breathing-related sleep disorders

Most individuals with a breathing-related sleep disorder have a history of loud snoring, breathing pauses during sleep, and excessive daytime sleepiness. Nonetheless, as many as 50% of individuals with sleep apnea may also report insomnia symptoms, a feature that is more common among females and older adults.

Narcolepsy

Narcolepsy may cause insomnia complaints but is distinguished from insomnia disorder by the predominance of symptoms of excessive daytime sleepiness, cataplexy, sleep paralysis, and sleep-related hallucinations.

Parasomnias

Parasomnias are characterized by a complaint of unusual behavior or events during sleep that may lead to intermittent awakenings and difficulty resuming sleep. However, it is these behavioral events, rather than the insomnia per se, that dominate the clinical picture.

Substance/medication-induced sleep disorder, insomnia type

Substance/medication-induced sleep disorder, insomnia type, is distinguished from insomnia disorder by the fact that a substance (i.e., a drug of abuse, a medication, or exposure to a toxin) is judged to be etiologically related to the insomnia disorder. For example, insomnia occurring only in the context of heavy coffee consumption would be diagnosed as caffeine-induced sleep disorder, insomnia type, with inset during intoxication.

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