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U.S. ICD-10-CM · FY 2027

F09 ICD-10-CM Code: Unspecified mental disorder due to known physiological condition

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

F09

Unspecified mental disorder due to known physiological condition

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where F09 sits

  1. 1

    Chapter 5

    Mental, Behavioral and Neurodevelopmental disorders (F01-F99)

  2. 2

    Section

    Mental disorders due to known physiological conditions (F01-F09)

  3. 3

    Category F09

    Unspecified mental disorder due to known physiological condition

  4. 4

    Code F09

    Unspecified mental disorder due to known physiological condition

Documentation details

Notes for this code

Inclusion terms

  • Mental disorder NOS due to known physiological condition
  • Organic brain syndrome NOS
  • Organic mental disorder NOS
  • Organic psychosis NOS
  • Symptomatic psychosis NOS

Code first

  • the underlying physiological condition

Use additional code

No “use additional code” instruction is listed for F09.

Excludes1

Conditions that should not be reported together with this code.

  • mild neurocognitive disorder due to known physiological condition (F06.7-)
  • psychosis NOS (F29)

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for F09.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

Publisher

Vero Scribe Inc.

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code F09 mean?

F09 is the FY 2027 U.S. ICD-10-CM code for “Unspecified mental disorder due to known physiological condition.”

Is F09 a billable or specific ICD-10-CM code?

Yes. In the FY 2027 reference data used on this page, F09 has no child codes and is presented as a billable/specific code. Always confirm the active code set and payer requirements before use.

Where is F09 located in ICD-10-CM?

F09 is listed in Chapter 5, Mental, Behavioral and Neurodevelopmental disorders (F01-F99), within Mental disorders due to known physiological conditions (F01-F09) (F01–F09), under category F09, Unspecified mental disorder due to known physiological condition.

What coding notes are listed for F09?

Its listed inclusion terms are Mental disorder NOS due to known physiological condition; Organic brain syndrome NOS; Organic mental disorder NOS; Organic psychosis NOS; Symptomatic psychosis NOS. Code-first instructions: the underlying physiological condition. Excludes1 notes: mild neurocognitive disorder due to known physiological condition (F06.7-); psychosis NOS (F29). No Excludes2 note is listed.

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