Diagnostic criteria - insomnia

International Classification of Sleep Disorders (ICSD-3) (2017)

• Per ICSD-3, this complaint must be present 3 or more nights per week, for at least 3 months, and be associated with impairment to day-time functioning or well-being
• Diagnostic criteria:
  • The patient reports (or the patient’s parent or caregiver reports) marked concern about, or dissatisfaction with, sleep comprising one or more of the following:
    • difficulty initiating sleep
    • difficulty maintaining sleep
    • waking up earlier than desired
    • resistance to going to bed on the appropriate schedule
    • difficulty sleeping without the parent or caregiver present
  • Occurs despite adequate opportunity and circumstances for sleep
  • At least one form of daytime impairment, for example:
    • fatigue
    • mood disturbance
    • interpersonal problems
    • reduced cognitive function
    • reduced performance
    • daytime sleepiness
    • behavioural problems (e.g. hyperactivity, impulsivity, aggression); reduced motivation/initiative
    • proneness to errors/ accidents.

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)

• a predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms:
  • difficulty initiating sleep. (in children, this may manifest as difficulty initiating sleep without caregiver intervention.)
  • 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.)
  • early-morning awakening with inability to return to sleep
• the sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioural, or other important areas of functioning
• the sleep difficulty occurs at least 3 nights per week.
• the sleep difficulty is present for at least 3 months
• the sleep difficulty occurs despite adequate opportunity for sleep
• 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)
• the insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication).
• coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia

DSM-5 also replaces primary insomnia with the diagnosis of "insomnia disorder"; this was done to avoid any primary/secondary designation when this disorder co-occurs with other conditions, and to reflect changes throughout the classification (2)

References:

1. Wilson S et al. British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders: An update. J Psychopharmacol. 2019 Aug;33(8):923-947
2. American Psychiatric Association. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5).