F09 ICD-10-CM Code: Unspecified mental disorder due to known physiological condition
F09 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
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FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Mental disorders due to known physiological conditions (F01-F09)
F09
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified mental disorder due to known physiological condition
A mental health disorder caused by a known medical condition when the specific type of mental disorder cannot be determined or is not specified.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Mental disorder NOS due to known physiological condition
- Organic brain syndrome NOS
- Organic mental disorder NOS
- Organic psychosis NOS
- Symptomatic psychosis NOS
Excludes 2
Official- symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)Inherited from F01-F99
Related Codes
No related codes are included in this display for F09. Check the Code Book for the complete code path.
Includes
Official- disorders of psychological developmentInherited from F01-F99
Excludes 1
Official- mild neurocognitive disorder due to known physiological condition (F06.7-)
- psychosis NOS (F29)
Code First
Official- the underlying physiological condition
Use Additional
OfficialNo Use Additional Code instructions are included in this display for F09. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for F09. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is F09 an HCC code?
No. F09 is a billable ICD-10-CM code with no mapping under the current CMS-HCC V28 community payment model, and none under the ESRD, Part D RxHCC, or HHS-HCC models.
- Code
- F09
- Description
- Unspecified mental disorder due to known physiological condition
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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What This Code Means
F09 is the ICD-10-CM diagnosis code for unspecified mental disorder due to known physiological condition. A mental health disorder caused by a known medical condition when the specific type of mental disorder cannot be determined or is not specified. F09 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental disorders due to known physiological conditions (f01-f09).
F09 is a billable ICD-10-CM code, but no current CMS-HCC V28 community payment mapping is shown, and none under the ESRD, Part D RxHCC, or HHS-HCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.
This is a catch-all code for mental disorders due to medical conditions that don't fit other specific categories.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for F09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a catch-all code for mental disorders due to medical conditions that don't fit other specific categories
- •Document the underlying medical condition and attempt to specify the mental disorder type when possible
Excludes 1, Do NOT code together
Code First
- the underlying physiological condition