F99 - Mental disorder, not otherwise specified

Version 2023
ICD-10:F99
Short Description:Mental disorder, not otherwise specified
Long Description:Mental disorder, not otherwise specified
Status: Valid for Submission
Version:ICD-10-CM 2023
Code Classification:
  • Mental and behavioural disorders (F00–F99)
    • Unspecified mental disorder (F99)
      • Mental disorder, not otherwise specified (F99)

F99 is a billable ICD-10 code used to specify a medical diagnosis of mental disorder, not otherwise specified. The code is valid during the fiscal year 2023 from October 01, 2022 through September 30, 2023 for the submission of HIPAA-covered transactions.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Clinical Information

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more. The following references are applicable to this diagnosis code:


Inclusion Terms

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.

Type 1 Excludes

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.

Index to Diseases and Injuries References

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for this diagnosis code are found in the injuries and diseases index:

Convert to ICD-9 Code

Source ICD-10 CodeTarget ICD-9 Code
F99300.9 - Nonpsychotic disord NOS
Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education


Mental Disorders

What are mental disorders?

Mental disorders (or mental illnesses) are conditions that affect your thinking, feeling, mood, and behavior. They may be occasional or long-lasting (chronic). They can affect your ability to relate to others and function each day.

What are some types of mental disorders?

There are many different types of mental disorders. Some common ones include:

What causes mental disorders?

There is no single cause for mental illness. A number of factors can contribute to risk for mental illness, such as:

Mental disorders are not caused by character flaws. They have nothing to do with being lazy or weak.

Who is at risk for mental disorders?

Mental disorders are common. More than half of all Americans will be diagnosed with a mental disorder at some time in their life.

How are mental disorders diagnosed?

The steps to getting a diagnosis include:

What are the treatments for mental disorders?

Treatment depends on which mental disorder you have and how serious it is. You and your provider will work on a treatment plan just for you. It usually involves some type of therapy. You may also take medicines. Some people also need social support and education on managing their condition.

In some cases, you may need more intensive treatment. You may need to go to a psychiatric hospital. This could be because your mental illness is severe. Or it could be because you are at risk of hurting yourself or someone else. In the hospital, you will get counseling, group discussions, and activities with mental health professionals and other patients.


[Learn More in MedlinePlus]

Code History