2026 ICD-10-CM Diagnosis Code R40.1Stupor

ICD-10-CM Codes›R00–R99›R40-R46›R40

ICD-10-CM R40.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R40.1 is a billable ICD-10-CM diagnosis code for stupor. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. Coders also document this condition as catatonic stupor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Coma; stupor; and brain damage.

Code Identity

ICD-10-CM Code
R40.1
Billable Status
Yes — Valid for Submission
Code Describes
Stupor
Short Description
Stupor
Same as the full description in the CMS dataset.
Parent Code
R40
Somnolence, stupor and coma

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR40-R46Symptoms and signs involving cognition, perception, emotional state and behavior
CategoryR40Somnolence, stupor and coma
This CodeR40.1Stupor

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Catatonic stupor
  • Clouded consciousness
  • Idiopathic catatonia
  • Idiopathic recurrent stupor
  • Semicoma
  • Stupor

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Catatonic stupor
  • Semicoma

Type 1 Excludes

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.

    • Catatonic
      • stupor
    • Clouded state
    • Semicoma
    • Stupor(catatonic)

Clinical ClassificationClinical

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

CCSR NVS013
Coma; stupor; and brain damage
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hepatic Encephalopathy

    a syndrome characterized by central nervous system dysfunction in association with liver failure, including portal-systemic shunts. clinical features include lethargy and confusion (frequently progressing to coma); asterixis; nystagmus, pathologic; brisk oculovestibular reflexes; decorticate and decerebrate posturing; muscle spasticity; and bilateral extensor plantar reflexes (see reflex, babinski). electroencephalography may demonstrate triphasic waves. (from adams et al., principles of neurology, 6th ed, pp1117-20; plum & posner, diagnosis of stupor and coma, 3rd ed, p222-5)

  • Stupor

    a state of reduced sensibility and response to stimuli which is distinguished from coma in that the person can be aroused by vigorous and repeated stimulation. the person is still conscious and can make voluntary movements. it can be induced by central nervous system agents. the word derives from latin stupere and is related to stunned, stupid, dazed or lethargy.

Convert R40.1 to ICD-9-CMHistory

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

ICD-9-CM
780.09 Other alter consciousnes
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 R40.1Overview

Is R40.1 (Somnolence, stupor and coma) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report stupor on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can R40.1 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the stupor is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R40.1?

Under the General Equivalence Mappings, stupor converts to ICD-9-CM 780.09 (other alter consciousnes). 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.