ICD-10 Code F43.21 – Adjustment disorder with depressed mood (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F43.21 – Adjustment disorder with depressed mood
What it is
F43.21 identifies an adjustment disorder where a clear stressor is followed by a depressed mood. You use it when the emotional response is out of proportion to the event and causes distress or impaired functioning.
Clinical signs
Common findings include low mood, tearfulness, hopelessness, and reduced interest after an identifiable stressor. Clinical features vary; refer to documentation for duration, severity, and whether symptoms meet adjustment disorder criteria.
When to use this code
Use this code when the record links depressive symptoms to an identifiable life stressor, such as loss, relationship change, or work-related difficulty. The clinician should document that the presentation is an adjustment disorder with depressed mood, not major depressive disorder.
If the note describes mixed anxiety and depression, or another adjustment subtype, check documentation before assigning F43.21. Use the most specific code supported by the assessment.
Do not use for
Do not use F43.21 for major depressive disorder, grief alone, or nonspecific sadness without an adjustment disorder diagnosis. Check documentation if the stressor and symptom pattern are unclear.
Coding tip
Confirm both the stressor and the provider’s specific adjustment disorder subtype before coding.