The predominant complaint in insomnia disorder is difficulty initiating or maintaining sleep, or nonrestorative sleep, occurring at least 3 nights per week for at least 3 months, despite adequate opportunity for sleep.

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

The sleep disturbance does not occur exclusively during the course of another, more predominant, sleep disorder, such as narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia.

The insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication). However, insomnia can occur alongside or as a result of a coexisting mental (e.g., major depressive disorder) or medical condition (e.g., pain) as long as the insomnia is significant enough to warrant its own clinical attention and treatment. For instance, insomnia may also manifest as a clinical feature of a more predominant mental disorder.

Persistent insomnia may 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 it is not necessary to make a causal attribution between the two conditions.

  • Episodic insomnia refers to when symptoms last at least 1 month but less than 3 months.
  • Persistent insomnia refers to chronic insomnia lasting 3 months or longer.
  • Recurrent insomnia refers to repeated episodes (1-3 month duration) of insomnia within the course of a year.

Learn more: Insomnia Treatment

This entry has been updated in line with DSM-5 criteria; diagnostic code: 307.42.