2026 ICD-10-CM Diagnosis Code F43.9Reaction to severe stress, unspecified

ICD-10-CM Codes›F01–F99›F40-F48›F43

ICD-10-CM F43.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F43.9 is a billable ICD-10-CM diagnosis code for reaction to severe stress, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as psychomotor agitation. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Trauma- and stressor-related disorders.

Code Identity

ICD-10-CM Code
F43.9
Billable Status
Yes — Valid for Submission
Code Describes
Reaction to severe stress, unspecified
Short Description
Reaction to severe stress, unspecified
Same as the full description in the CMS dataset.
Parent Code
F43
Reaction to severe stress, and adjustment disorders

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF40-F48Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders
CategoryF43Reaction to severe stress, and adjustment disorders
This CodeF43.9Reaction to severe stress, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Psychomotor agitation
  • Stress and adjustment reaction
  • Stress due to family tension
  • Stress monitoring check done
  • Stress monitoring default
  • Stress monitoring status
  • Stress reaction with psychomotor agitation
  • Symptoms of stress

Tabular List NotesGuidance

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

Inclusion Terms

  • Trauma and stressor-related disorder, NOS
  • Unspecified trauma and stressor-related disorder

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)
      • stress
    • Disorder(of)
      • trauma and stressor-related NOS
    • Disorder(of)
      • trauma and stressor-related NOS
        • unspecified
    • Reaction
      • stress (severe)
    • Stress
    • Stress
      • reaction

Clinical ClassificationClinical

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

CCSR MBD007
Trauma- and stressor-related disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Psychomotor Agitation

    a feeling of restlessness associated with increased motor activity. this may occur as a manifestation of nervous system drug toxicity or other conditions.

Patient EducationClinical

Stress

Stress is how your brain and body respond to a challenge or demand. When you are stressed, your body releases certain hormones. Hormones are chemicals that travel in your bloodstream and control how different parts of your body work. The hormones that are released when you are stressed make you alert and ready to act.

The full article covers:

  • What is stress?
  • What causes long-term stress?
  • How can long term-stress harm my health?
  • How can I manage long-term stress?
  • When should I ask my health care provider for help with stress?

Read the full article at MedlinePlus

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

Convert F43.9 to ICD-9-CMHistory

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

ICD-9-CM
309.9 Adjustment reaction NOS
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 F43.9Overview

Is F43.9 (Reaction to severe stress, and adjustment disorders) a billable code?

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

What is the ICD-9 equivalent of F43.9?

Under the General Equivalence Mappings, reaction to severe stress, unspecified converts to ICD-9-CM 309.9 (adjustment reaction NOS). 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.