ICD-10 Code F16.921 – Hallucinogen use, unspecified with intoxication with delirium (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F16.921 – Hallucinogen use, unspecified with intoxication with delirium
What it is
This code identifies hallucinogen use, type unspecified, when intoxication is complicated by delirium. Use it when the record shows acute hallucinogen-related confusion and altered awareness, but the specific substance is not named.
Clinical signs
Typical findings include disturbed attention, disorganized thinking, reduced awareness of the environment, and fluctuating confusion. Clinical features vary; refer to documentation for signs of intoxication and delirium.
When to use this code
Use this code when a clinician documents hallucinogen use with intoxication and delirium, and the hallucinogen is not specified. It fits emergency or inpatient notes describing acute mental status change linked to recent use. If the substance is identified, check for a more specific code.
Do not use for
Do not use this code for hallucinations without delirium, or for intoxication without documented delirium. If the record describes another substance or a different mental disorder, choose the appropriate code.
Coding tip
Verify that both intoxication and delirium are documented before assigning F16.921.