---
title: "ICD-10-CM F99: Mental disorder, not otherwise specified | BillingBrief"
description: "ICD-10-CM code F99: Mental disorder, not otherwise specified. Category, related codes, and the official source, in plain English."
canonical: "https://billingbrief.com/icd10/f99/"
language: "en"
---

# F99 Mental disorder, not otherwise specified

ICD-10-CM · [CMS code reference](#source)

**Official ICD-10-CM description:** Mental disorder, not otherwise specified

## Common questions

### Is F99 a billable code?

Yes. F99 is a billable ICD-10-CM code in the ICD-10-CM FY2027 (effective October 1, 2026) code set.

## From the source

Official description from [CMS](https://www.cms.gov/medicare/coding-billing/icd-10-codes).
ICD-10-CM FY2027 (effective October 1, 2026).

Code set

ICD-10-CM

Category

F99 Mental disorder, not otherwise specified

Chapter

Mental, behavioral and neurodevelopmental disorders

Billable

Yes

Educational reference only. Not medical, legal, or billing advice. Always check the current official code set and payer policy before you bill. [About BillingBrief and our sources](https://billingbrief.com/about/).