F18.259
BillableInhalant dependence with inhalant-induced psychotic disorder, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F18.259 an HCC code?
Yes. F18.259 maps to Drug/Alcohol Psychosis under the CMS-HCC V28 risk adjustment model (and Drug/Alcohol Psychosis under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for F18.259
For F18.259 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed F18.259 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F18.259 is the ICD-10-CM diagnosis code for inhalant dependence with inhalant-induced psychotic disorder, unspecified. This code describes a person who is dependent on inhalant substances (like glue, paint thinner, or aerosols) and has developed a psychotic disorder as a result, but the specific type of psychotic symptoms is not specified. The psychotic symptoms may include hallucinations, delusions, or disorganized thinking caused by the inhalant use. F18.259 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental and behavioral disorders due to psychoactive substance use (f10-f19).
Under the CMS-HCC V28 risk adjustment model, F18.259 maps to Drug/Alcohol Psychosis (HCC 135) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, F18.259 mapped to the same category but with a base RAF weight of 0.434 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Verify documentation clearly states both inhalant dependence AND inhalant-induced psychotic disorder to justify this combination code; do not use if only one condition is present. Because F18.259 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F18.259 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation clearly states both inhalant dependence AND inhalant-induced psychotic disorder to justify this combination code; do not use if only one condition is present
- •If the specific type of psychotic disorder is documented (such as with delusions or with hallucinations), use the more specific subcategories F18.251 or F18.252 instead of the unspecified code F18.259
Clinical Significance
Inhalant dependence with unspecified psychotic disorder captures substance-induced psychosis when the documentation does not clarify whether delusions or hallucinations predominate. Despite being unspecified, this still maps to HCC 54, the highest substance use category, making documentation of any psychotic features important.
Documentation Requirements
- ✓Documentation of inhalant dependence with psychotic symptoms
- ✓Evidence of psychosis linked to inhalant use
- ✓Provider query for specific psychotic features
- ✓Mental status examination documenting psychotic symptoms
- ✓Differentiation from delirium and primary psychotic disorders