2026 ICD-10-CM Diagnosis Code F43.20Adjustment disorder, unspecified

ICD-10-CM Codes›F01–F99›F40-F48›F43

ICD-10-CM F43.20
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F43.20 is a billable ICD-10-CM diagnosis code for adjustment disorder, unspecified. 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 Trauma- and stressor-related disorders.

Code Identity

ICD-10-CM Code
F43.20
Billable Status
Yes — Valid for Submission
Code Describes
Adjustment disorder, unspecified
Short Description
Adjustment disorder, unspecified
Same as the full description in the CMS dataset.
Parent Code
F43.2
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 CodeF43.20Adjustment disorder, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal grief reaction
  • Acute situational disturbance
  • Acute stress disorder
  • Adjustment disorder
  • Adjustment disorder during pregnancy
  • Adjustment disorder in remission
  • Adjustment reaction in infancy
  • Adjustment reaction of adolescence
  • Adjustment reaction of adult life
  • Adjustment reaction of childhood
  • Adjustment reaction of late life
  • Adjustment reaction to medical therapy
  • Culture shock
  • Difficulty adapting after personal crisis
  • Difficulty coping
  • Difficulty coping with grief responses
  • Does not adapt after personal crisis
  • Dysfunctional grieving
  • Elective mutism due to an adjustment reaction
  • Fails to recognize stages of grief
  • Grieving process stage - finding
  • Hospitalism
  • Persistent adjustment disorder
  • Postpartum adjustment disorder
  • Stress and adjustment reaction
  • Stress-related problem
  • Unable to adapt after personal crisis

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)
      • adjustment (grief)
    • Grief
      • reaction
    • Nostalgia

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

  • Acute Stress Disorder

    an anxiety disorder precipitated by an experience of intense fear or horror while exposed to a traumatic (especially life-threatening) event. the disorder is characterized by dissociative symptoms; vivid recollections of the traumatic event; avoidance of stimuli associated with the traumatic event; and a constant state of hyperarousal for no more than one month.

Patient EducationClinical

Mental Disorders

Mental disorders (or mental illnesses) are conditions that affect your thinking, feeling, mood, and behavior. They may happen over a short period of time or come and go. Some can be chronic (long-lasting). They can affect your ability to relate to others and function each day..

The full article covers:

  • What are mental disorders?
  • What are some types of mental disorders?
  • What causes mental disorders?
  • Who is at risk for mental disorders?
  • How are mental disorders diagnosed?
  • What are the treatments for mental disorders?

Read the full article at MedlinePlus

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

Convert F43.20 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 F43.20Overview

Is F43.20 (Adjustment disorders) a billable code?

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

What is the ICD-9 equivalent of F43.20?

Under the General Equivalence Mappings, adjustment disorder, 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.