2021 ICD-10-CM Code F99
Mental disorder, not otherwise specified
Valid for Submission
F99 is a billable diagnosis code used to specify a medical diagnosis of mental disorder, not otherwise specified. The code F99 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.
The ICD-10-CM code F99 might also be used to specify conditions or terms like axis i diagnosis, axis ii diagnosis, axis iii diagnosis, axis iv diagnosis, axis v diagnosis , brain fag, etc.
| ICD-10: | F99 |
| Short Description: | Mental disorder, not otherwise specified |
| Long Description: | Mental disorder, not otherwise specified |
Code Classification
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 the code F99:
Inclusion Terms
Inclusion TermsThese 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.
- Mental illness NOS
Type 1 Excludes
Type 1 ExcludesA 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.
- unspecified mental disorder due to known physiological condition F09
Index to Diseases and Injuries
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 the code F99 are found in the index:
- - Aberration
- - mental - F99
- - Disease, diseased - See Also: Syndrome;
- - mental - F99
- - psychiatric - F99
- - Disorder (of) - See Also: Disease;
- - mental (or behavioral) (nonpsychotic) - F99
- - psychological - F99
- - Disturbance (s) - See Also: Disease;
- - mental - F99
- - Psychiatric disorder or problem - F99
- - Reaction - See Also: Disorder;
- - psychogenic - F99
- - Situation, psychiatric - F99
Approximate Synonyms
The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:
- Axis I diagnosis
- Axis II diagnosis
- Axis III diagnosis
- Axis IV diagnosis
- Axis V diagnosis
- Brain fag
- Cheshire cat syndrome
- Chronic mental disorder
- Deferred diagnosis on Axis II
- Deferred diagnosis on Axis III
- Female athlete triad
- Ghost sickness
- Hypersomnia disorder related to another mental disorder
- Identity disorder
- Impairment of psychological status
- Indication for modification of patient physical status
- Indication for modification of patient psychological status
- Indication for modification of patient status
- Indication for modification of patient status
- Insomnia disorder related to another mental disorder
- Intensive care psychiatric disorder
- Lifelong psychologic disorder
- Mental disorder
- Mental disorder AND/OR culture bound syndrome
- Mental disorder during pregnancy - baby delivered
- Mental disorder during pregnancy - baby not yet delivered
- Mental disorder in infancy
- Mental disorder in mother complicating childbirth
- Mental disorder in mother complicating pregnancy
- Mental disorder in the puerperium - baby delivered
- Mental disorder in the puerperium - baby delivered during previous episode of care
- Mental disorders during pregnancy, childbirth and the puerperium
- On severe mental illness register
- Pregnancy with mental disorders
- Psychiatric behavioral disability
- Psychiatric treatment changed
- Psychiatric treatment started
- Psychological disorder during pregnancy
- Root work
- Suspicion
Convert F99 to ICD-9 Code
The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code F99 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.
- 300.9 - Nonpsychotic disord NOS (Approximate Flag)
Information for Patients
Mental Disorders
Also called: Mental illness
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
- Anxiety disorders, including panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, and phobias
- Depression, bipolar disorder, and other mood disorders
- Eating disorders
- Personality disorders
- Psychotic disorders, including schizophrenia
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
- Your genes and family history
- Your life experiences, such as stress or a history of abuse, especially if they happen in childhood
- Biological factors such as chemical imbalances in the brain
- A traumatic brain injury
- A mother's exposure to viruses or toxic chemicals while pregnant
- Use of alcohol or recreational drugs
- Having a serious medical condition like cancer
- Having few friends, and feeling lonely or isolated
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
- A medical history
- A physical exam and possibly lab tests, if your provider thinks that other medical conditions could be causing your symptoms
- A psychological evaluation. You will answer questions about your thinking, feelings, and behaviors.
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.
- Adjustment disorder (Medical Encyclopedia)
- Conversion disorder (Medical Encyclopedia)
- Illness anxiety disorder (Medical Encyclopedia)
- Somatic symptom disorder (Medical Encyclopedia)
[Learn More in MedlinePlus]
Code History
- FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
- FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
- FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
- FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
- FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
- FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)