ICD-10 Code F16.121 – Hallucinogen Abuse with Intoxication with Delirium (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F16.121 – Hallucinogen abuse with intoxication with delirium
What it is
Use this code for hallucinogen abuse when intoxication is accompanied by delirium. It describes a substance-related mental status change with impaired awareness, confusion, and disorganized thinking.
Clinical signs
Clinical features vary; refer to documentation. Delirium may include altered attention, disorientation, agitation, perceptual disturbance, or fluctuating consciousness after hallucinogen use.
When to use this code
Use F16.121 when the record clearly links hallucinogen abuse to intoxication with delirium. The provider should document both the substance use and the delirium during the intoxication episode. If the chart does not specify delirium, check documentation before assigning this code.
Do not use for
Do not use this code for hallucinogen use without abuse, or for intoxication without delirium. If the documentation identifies dependence, remission, or another substance-related disorder, select the more specific code.
Coding tip
Verify that delirium is explicitly documented as part of the intoxication, not just confusion or anxiety.