2026 ICD-10-CM Diagnosis Code F28Other psychotic disorder not due to a substance or known physiological condition

ICD-10-CM Codes›F01–F99›F20-F29›F28

ICD-10-CM F28
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F28 is a billable ICD-10-CM diagnosis code for other psychotic disorder not due to a substance or known physiological condition. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 974 through 976. Coders also document this condition as hallucinosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Schizophrenia spectrum and other psychotic disorders.

Code Identity

ICD-10-CM Code
F28
Billable Status
Yes — Valid for Submission
Code Describes
Other psychotic disorder not due to a substance or known physiological condition
Chapter
F20-F29
Schizophrenia, schizotypal, delusional, and other non-mood psychotic disorders

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF20-F29Schizophrenia, schizotypal, delusional, and other non-mood psychotic disorders
CategoryF28Other psychotic disorder not due to a substance or known physiological condition
This CodeF28Other psychotic disorder not due to a substance or known physiological condition

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hallucinosis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Chronic hallucinatory psychosis
  • Other specified schizophrenia spectrum and other psychotic disorder

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • schizophrenia spectrum and other psychotic disorder
        • specified NEC
    • Hallucinosis(chronic)
    • Insanity, insane
      • confusional
    • Menopause, menopausal(asymptomatic) (state)
      • psychosis NEC
    • Psychosis, psychotic
      • hallucinatory, chronic
    • Psychosis, psychotic
      • involutional
    • Psychosis, psychotic
      • nonorganic
        • specified NEC
    • Schizophrenia, schizophrenic
      • spectrum and other psychotic disorder
        • specified NEC

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MBD001
Schizophrenia spectrum and other psychotic disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Psychotic Disorders

Psychotic disorders are severe mental disorders that cause abnormal thinking and perceptions. People with psychoses lose touch with reality. Two of the main symptoms are delusions and hallucinations. Delusions are false beliefs, such as thinking that someone is plotting against you or that the TV is sending you secret messages.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert F28 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
298.9 Psychosis NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F28Overview

Is F28 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other psychotic disorder not due to a substance or known physiological condition on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does F28 group to?

When other psychotic disorder not due to a substance or known physiological condition is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 975, 976, with relative weights from 0.8945 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of F28?

Under the General Equivalence Mappings, other psychotic disorder not due to a substance or known physiological condition converts to ICD-9-CM 298.9 (psychosis NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.