ICD-10-CM F43.21

ICD-10 Code F43.21: Adjustment disorder with depressed mood

F43.21 is the ICD-10-CM code for adjustment disorder with depressed mood. It applies when the reaction to an identifiable stressor shows up mainly as low mood.

Official description

Adjustment disorder with depressed mood

Billable

Yes

Parent category

F43.2 · Adjustment disorders

DSM-5-TR name

Adjustment disorder, with depressed mood

Verified against the FY2027 ICD-10-CM code set (CDC/NCHS and CMS), effective October 1, 2026 - September 30, 2027, on Oct 12, 2026. Chapter 5: Mental, Behavioral and Neurodevelopmental disorders (F01-F99).

Coding notes for F43.21

• Depressed mood is the predominant presentation
• If anxiety is also prominent, F43.23 (mixed) is more accurate
• If criteria for a major depressive episode are met, the F32 or F33 code applies instead

What to document for medical necessity

Payers look for a record that supports the diagnosis and the level of care. For adjustment disorders that usually means:

• The identifiable stressor and when it started
• The predominant symptoms, which decide the sixth character
• Why the reaction is out of proportion to the stressor or impairs functioning
• A review date - adjustment disorders are expected to be time-limited, so revisit the code if symptoms persist
• Treatment plan goals tied to the stressor and the symptoms

CPT codes often billed with F43.21

The ICD-10 code says why you are treating the client and the CPT code says what you did. These are the service codes most often paired with F43.21:

Free templates for this diagnosis

• Initial intake assessment
• Comprehensive treatment plan
• Insurance DAP note

Related ICD-10 codes

Frequently asked questions

This page is a coding reference, not clinical, diagnostic, billing, or legal advice. The diagnosis is the treating clinician's call, and payer rules vary - always confirm against the current ICD-10-CM code set and official guidelines and your payer's policy. See the full mental health ICD-10 code list.