Hypersomnolence Disorder 369
F. Coexisting mental and medical disorders do not adequately explain the predominant
complaint of hypersomnolence.
Specify if:
With mental disorder , including substance use disorders
With medical condition
With another sleep disorder
Coding note: The code 307.44 (F51.11) applies to all three specifiers. Code also the
relevant associated mental disorder, medi cal condition, or other sleep disorder im-
mediately after the code for hypersomnolence disorder in order to indicate the associ-
ation.
Specify if:
Acute:  Duration of less than 1 month.
Subacute:  Duration of 1–3 months.
Persistent:  Duration of more than 3 months.
Specify current severity:
Specify severity based on degree of difficulty maintaining daytime alertness as manifested
by the occurrence of multiple attacks of irresistible sleepiness within any given day occur-
ring, for example, while sedentary, driving, visiting with friends, or working. 
Mild:  Difficulty maintaining daytime alertness 1–2 days/week.
Moderate: Difficulty maintaining daytime alertness 3–4 days/week.
Severe:  Difficulty maintaining daytime alertness 5–7 days/week.
Diagnostic Features
Hypersomnolence  is a broad diagnostic term and incl udes symptoms of excessive quantity
of sleep (e.g., extended nocturnal sleep or involuntary daytime sleep),  deteriorated quality
of wakefulness (i.e., sleep propensity duri ng wakefulness as shown by difficulty awaken-
ing or inability to remain awake when required ), and sleep inertia (i.e., a period of im-
paired performance and reduced vigilance following awakening from the regular sleep
episode or from a nap) (Criterion A). Indivi duals with this disorder fall asleep quickly and