Table 1.

Summary of insomnia diagnoses across classification systems

	DSM-IV	ICSD-2	DSM-V (Proposed)
Diagnosis for primary insomnia	Primary insomnia (307.42)	Psychophysiological insomnia (307.42)	Insomnia disorder
		Paradoxical insomnia (307.42)
		idiopathic insomnia (307.42)
Comorbid insomnia disorder	Sleep disorder due to general medical condition, insomnia type (327.01)	Insomnia due to medical condition (327.01)	No separate category; includes specifier to clarify comorbid physical or mental illness
	Insomnia related to another mental disorder (327.02)	Insomnia due to mental disorder (327.02)
Duration	Difficulty initiating or maintaining sleep, or nonrestorative sleep for at least 1 month	Not specified	Sleep difficulty occurs at least 3 nights per week, for at least 3 months
Other subtypes of insomnia	Substance-induced insomnia	Adjustment insomnia, inadequate sleep hygiene, insomnia due to drug or substance, insomnia unspecified and physiological insomnia	Not yet specified

The ICSD-2 classifies insomnia disorders as subtypes based on presumed etiology

ICSD-2 = International Classification of Sleep Disorders, 2nd edition; DSM-IV = Diagnostic and Statistical Manual for Mental Disorders, 4th edition