Sleep disorders not due to a substance or known physiological condition (F51) ICD-10-CM
The F51 code range covers sleep disorders not due to a substance or known physiological condition with 18 ICD-10-CM diagnosis codes. 15 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- organic sleep disorders G47
Codes in the F51 Range 18 codes · 15 billable
- F51 Sleep disorders not due to a substance or known physiological conditionNon-billable
- F51.0 Insomnia not due to a substance or known physiological conditionNon-billable
- F51.01 Primary insomnia
- F51.02 Adjustment insomnia
- F51.03 Paradoxical insomnia
- F51.04 Psychophysiologic insomnia
- F51.05 Insomnia due to other mental disorder
- F51.09 Other insomnia not due to a substance or known physiological condition
- F51.1 Hypersomnia not due to a substance or known physiological conditionNon-billable
- F51.11 Primary hypersomnia
- F51.12 Insufficient sleep syndrome
- F51.13 Hypersomnia due to other mental disorder
- F51.19 Other hypersomnia not due to a substance or known physiological condition
- F51.3 Sleepwalking [somnambulism]
- F51.4 Sleep terrors [night terrors]
- F51.5 Nightmare disorder
- F51.8 Other sleep disorders not due to a substance or known physiological condition
- F51.9 Sleep disorder not due to a substance or known physiological condition, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the F51 range.
Idiopathic Hypersomnia
A disorder of central nervous system etiology characterized by excessive sleepiness during the daytime.
Nightmare Disorder
A sleep disorder characterized by the repeated occurrence of frightening dreams which precipitate awakenings from sleep; on awakening, the individual becomes fully alert and oriented and has detailed recall of the nightmare, which usually involves imminent danger or extreme embarrassment to the individual.
Primary Insomnia
A sleep disorder characterized by difficulty initiating or maintaining sleep; this difficulty does not occur in the context of another sleep disorder and is not etiologically linked to a mental disorder, substance use, or a general medical condition.
Somnambulism
A parasomnia characterized by a partial arousal that occurs during stage IV of non-REM sleep. Affected individuals exhibit semipurposeful behaviors such as ambulation and are difficult to fully awaken. Children are primarily affected, with a peak age range of 4-6 years.
About the F51 Code Range
These sleep problems are not due to a substance or a known physical condition. They include difficulty sleeping, excessive sleepiness, sleepwalking, sleep terrors, and nightmares.
F51.0 groups insomnia, or difficulty sleeping, by forms such as primary, adjustment, paradoxical, psychophysiologic, and insomnia due to another mental disorder. F51.1 groups hypersomnia, or excessive sleepiness, by primary, insufficient sleep syndrome, mental disorder-related, and other forms.
Separate codes identify sleepwalking, sleep terrors, and nightmare disorder. The category also has codes for other and unspecified sleep disorders.
Questions About This Page
How many billable codes are in the F51 range?
Of the 18 codes in this range, 15 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the F51 range classify?
The range classifies sleep disorders not due to a substance or known physiological condition. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
