2026 ICD-10-CM Diagnosis Code F51.8Other sleep disorders not due to a substance or known physiological condition

ICD-10-CM Codes›F01–F99›F50-F59›F51

ICD-10-CM F51.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F51.8 is a billable ICD-10-CM diagnosis code for other sleep disorders not due to a substance or known physiological condition. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sleep wake disorders.

Code Identity

ICD-10-CM Code
F51.8
Billable Status
Yes — Valid for Submission
Code Describes
Other sleep disorders not due to a substance or known physiological condition
Short Description
Oth sleep disord not due to a sub or known physiol cond
Parent Code
F51
Sleep disorders not due to a substance or known physiological condition

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF50-F59Behavioral syndromes associated with physiological disturbances and physical factors
CategoryF51Sleep disorders not due to a substance or known physiological condition
This CodeF51.8Other sleep disorders not due to a substance or known physiological condition

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bizarre dreams
  • Detailed recall of dream
  • Dream disorder
  • Environmental sleep disorder
  • Long sleeper syndrome
  • Non-organic parasomnia
  • Non-organic sleep disorder
  • Repetitive dreams
  • Repetitive intrusions of sleep
  • Short-sleeper

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • sleep
        • nonorganic
          • specified NEC
    • Parasomnia
      • nonorganic origin

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS016
Sleep wake disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Sleep Disorders

Sleep is a complex biological process. While you are sleeping, you are unconscious, but your brain and body functions are still active. They are doing a number of important jobs that help you stay healthy and function at your best. So when you don't get enough quality sleep, it does more than just make you feel tired.

The full article covers:

  • What is sleep?
  • What are sleep disorders?
  • What causes sleep disorders?
  • What are the symptoms of sleep disorders?
  • How are sleep disorders diagnosed?
  • What are the treatments for sleep disorders?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert F51.8 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
307.49 Nonorganic sleep dis NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F51.8Overview

Is F51.8 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other sleep disorders not due to a substance or known physiological condition on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of F51.8?

Under the General Equivalence Mappings, other sleep disorders not due to a substance or known physiological condition converts to ICD-9-CM 307.49 (nonorganic sleep dis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.