ICD-10-CM code · FY2027

F99 Mental disorder, not otherwise specified

BillableValid for claims as a specific diagnosis code

About F99

Code: F99
Billable: Yes
Short description: Mental disorder, not otherwise specified
Block: F99 Unspecified mental disorder (F99)
Chapter: 5 Mental, Behavioral and Neurodevelopmental disorders
Code set: FY2027, October 1, 2026 to September 30, 2027

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Coding notes for F99

Applicable to Other names for conditions reported with this code.

Mental illness NOS

Excludes1 Not coded here: never report these together with this code (use the code given instead).

unspecified mental disorder due to known physiological condition (F09)

Chapter 5 notes (apply to every code in it)

Includes Conditions this code covers.

disorders of psychological development

Excludes2 Not part of this condition, but a patient can have both: report both codes when both apply.

symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Latest research on mental disorder

Prenatal Systemic Glucocorticoid Exposure and an Increased Risk of Future Mental DisordersJan 16, 2025
Prenatal systemic glucocorticoid exposure may be associated with increased risk of future mental disorderJan 10, 2025 · Chronic Disease
Cases of neurodevelopmental disorders caused by mutated lncRNA CHASERRNov 25, 2024 · Chronic Disease
Prenatal exposure to maternal autoimmune diseases associated with increased risks of mental disorders in offspringApr 20, 2022 · Chronic Disease
Prenatal exposure to antipsychotic medications not associated with increased risk of neurodevelopmental disorders in offspringMar 30, 2022 · Obstetrics

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ICD-10-CM FY2027 code set, as published by the CDC National Center for Health Statistics (NCHS) and CMS, effective October 1, 2026 to September 30, 2027. Codes, titles and notes are shown as published. Check payer rules and the official guidelines before billing. This page is not medical advice.