Unspecified mental disorder due to known physiological condition (F09) ICD-10-CM
The F09 code range covers unspecified mental disorder due to known physiological condition with 1 ICD-10-CM diagnosis codes. 1 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
- Mental disorder NOS due to known physiological condition
- Organic brain syndrome NOS
- Organic mental disorder NOS
- Organic psychosis NOS
- Symptomatic psychosis NOS
Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- the underlying physiological condition
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Codes in the F09 Range 1 codes · 1 billable
- F09 Unspecified mental disorder due to known physiological condition
About the F09 Code Range
The ICD-10 code F09 is used to classify unspecified mental disorders that arise from a known physiological condition. It captures cases where a medical cause for the mental disorder is recognized, but the specific mental health features are not distinctly classified.
This code covers a broad range of conditions often referred to by synonyms such as organic mental disorder, neurocognitive disorder, or chronic organic mental disorder. It includes mental changes linked with systemic illnesses like lupus or HIV/AIDS, and cognitive or behavioral disorders triggered by substances such as ethanol, sedatives, or hypnotic agents. Conditions like transient organic mental disorders or cognitive and behavior disorders following brain injury also fall under this code. Using ICD-10 code F09 helps healthcare professionals accurately record mental disorders influenced significantly by physical causes, even when the precise mental symptoms are not otherwise specified, ensuring clarity when coding complex organic brain syndromes and associated cognitive impairments.
Questions About This Page
How many billable codes are in the F09 range?
Of the 1 codes in this range, 1 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the F09 range classify?
The range classifies unspecified mental disorder due to known physiological condition. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
