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ICD-10 Guide
ICD-10 CodesChapter 5: Mental, Behavioral and Neurodevelopmental disordersF09

F09

Billable

Unspecified mental disorder due to known physiological condition

Chapter 5:Mental, Behavioral and Neurodevelopmental disorders

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 F09 is a billable code used to indicate a diagnosis of unspecified mental disorder due to known physiological condition.

Key Diagnostic Point:

F09 is used to classify mental disorders that arise as a direct result of a known physiological condition. These disorders can manifest as organic mental disorders, which include cognitive impairments, delirium, and personality changes. The physiological conditions may range from metabolic disorders, neurological diseases, infections, or substance-induced conditions. Clinically, patients may present with confusion, altered consciousness, mood disturbances, or significant changes in personality and behavior. The diagnosis requires careful evaluation to establish a clear link between the physiological condition and the mental disorder, ensuring that the mental symptoms are not better explained by other psychiatric diagnoses. This code is particularly important in cases where the specific nature of the mental disorder cannot be precisely categorized, yet the physiological basis is evident. Accurate documentation of the underlying condition and the mental symptoms is crucial for proper coding and treatment planning.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Need for comprehensive documentation linking physiological conditions to mental disorders.
  • Variability in presentation of symptoms based on underlying conditions.
  • Differentiation from other mental health diagnoses.
  • Potential overlap with other ICD-10 codes for mental disorders.

Audit Risk Factors

  • Inadequate documentation linking mental disorder to physiological condition.
  • Misclassification of symptoms leading to incorrect coding.
  • Failure to update codes based on changes in patient condition.
  • Lack of interdisciplinary notes that support the diagnosis.

Specialty Focus

Medical Specialties

Psychiatry

Documentation Requirements

Detailed psychiatric evaluation notes linking mental symptoms to physiological conditions.

Common Clinical Scenarios

Patients with dementia secondary to neurological disorders, delirium due to infections.

Billing Considerations

Ensure that all relevant medical history and physiological assessments are documented.

Neurology

Documentation Requirements

Neurological assessments and imaging results that correlate with mental health symptoms.

Common Clinical Scenarios

Patients with traumatic brain injuries presenting with personality changes.

Billing Considerations

Collaboration with psychiatry for comprehensive care and documentation.

Coding Guidelines

Inclusion Criteria

Use F09 When
  • According to ICD
  • 10 guidelines, F09 should be used when a mental disorder is clearly linked to a known physiological condition, and no other specific mental disorder code applies
  • Coders must ensure that the physiological condition is documented and that the mental symptoms are not better explained by other psychiatric diagnoses

Exclusion Criteria

Do NOT use F09 When
No specific exclusions found.

Related CPT Codes

90791CPT Code

Psychiatric diagnostic evaluation

Clinical Scenario

Used when evaluating a patient with F09 to establish a diagnosis.

Documentation Requirements

Comprehensive evaluation notes detailing mental and physiological assessments.

Specialty Considerations

Psychiatrists should ensure interdisciplinary communication for accurate diagnosis.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of mental disorders, including those due to physiological conditions. F09 provides a necessary option for cases where the mental disorder cannot be precisely categorized, ensuring that patients receive appropriate care and treatment.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of mental disorders, including those due to physiological conditions. F09 provides a necessary option for cases where the mental disorder cannot be precisely categorized, ensuring that patients receive appropriate care and treatment.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of mental disorders, including those due to physiological conditions. F09 provides a necessary option for cases where the mental disorder cannot be precisely categorized, ensuring that patients receive appropriate care and treatment.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

When should I use F09 instead of a more specific code?

F09 should be used when a mental disorder is present due to a known physiological condition, but the specific nature of the mental disorder cannot be accurately classified. Ensure that documentation supports this coding choice.