F09 Unspecified mental disorder due to known physiological condition

ICD-10-CM F09: Unspecified Mental Disorder Due to Known Physiological Condition

ICD-10-CM code F09 represents an unspecified mental disorder due to a known physiological condition. Mental disorders broadly affect an individual's thinking, feeling, mood, or behavior. The sources establish that mental health conditions are diagnosed using clinical guidelines, and they distinguish mental disorders from non-diagnostic behavioral codes. The provided excerpts do not detail specific clinical criteria for F09. 1 2 4 6

Plain-language overview

Mental health conditions are illnesses that affect a person's thinking, feeling, behavior, or mood. Healthcare professionals use guidelines in the Diagnostic and Statistical Manual of Mental Disorders to diagnose these mental health conditions. 4

What this code represents

Code F09 is named unspecified mental disorder due to known physiological condition. Its semantic type is classified as a mental or behavioral dysfunction. 6

Coding details

The F09 code is listed alongside other mental disorders due to known physiological conditions, such as mood disorder and psychotic disorder with hallucinations. It is distinct from sleep disorders not due to a substance or known physiological condition. 5

Documentation considerations

The Diagnostic and Statistical Manual of Mental Disorders Fifth Edition, Text Revision provides uniform criteria for diagnosis. "V" coded conditions listed in the DSM are not diagnoses but are used when the focus is on a behavior not due to a mental disorder. 2

What the sources add

The CDC source defines mental health conditions as illnesses affecting thinking or mood, while the NCBI source describes mental health disorders as affecting thinking, feeling, mood, or behavior and including conditions like depression and anxiety. 1 4

The CDC source states that the presence of chronic conditions can increase the risk for developing a mental health condition. The NCBI source notes that chronic pain may contribute to an increased risk for mental health disorders. 1 4

Clinical context

Mental conditions and chronic pain often occur together, but the causal pathway or direction of the association is debated. Individuals with mental conditions comorbid with chronic pain were more likely to be among the most disabled than those with neither. 1

Coverage and utilization context

Medical screening for physical and mental disorders with associated harmful behaviors is an essential component of the U.S. immigration process. Mental disorders that have associated harmful behaviors are inadmissible Class A conditions. 2

Sources

1. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Mental Health — cdc.gov; accessed 2026-07-25.
3. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-25.
4. About Mental Health — cdc.gov; accessed 2026-07-25.
5. ICD-10-CM/PCS MS-DRGv33 Definitions Manual — cms.gov; accessed 2026-07-25.
6. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-25.