F99

Billable

Mental disorder, not otherwise specified

F99 is the ICD-10-CM code for Mental disorder, not otherwise specified. It is a billable, specific code valid for reimbursement.

Status
Billable
Chapter
F01-F99
Edition
FY2026

F01-F99 Mental, Behavioral and Neurodevelopmental disorders

Includes

  • Mental illness NOS

Excludes1 — not coded here

  • unspecified mental disorder due to known physiological condition (F09)

Frequently asked questions

What is ICD-10 code F99?
F99 is the ICD-10-CM code for "Mental disorder, not otherwise specified". It falls under F01-F99 Mental, Behavioral and Neurodevelopmental disorders.
Is F99 a billable code?
Yes — F99 is a billable, specific ICD-10-CM code valid for reimbursement.
What is excluded from F99?
Excludes1 (not coded here): unspecified mental disorder due to known physiological condition (F09).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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