ICD-10 Code F16.99 – Hallucinogen use, unspecified with unspecified hallucinogen-induced disorder (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F16.99 – Hallucinogen use, unspecified with unspecified hallucinogen-induced disorder
What it is
This code identifies hallucinogen use when the specific substance is not documented and the induced mental or behavioral disorder is also not specified. Use it when the record confirms hallucinogen-related harm but does not name a more precise diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Hallucinogen-induced disorders may include perceptual changes, altered thinking, mood disturbance, or behavioral changes, but the chart must support a hallucinogen-related disorder rather than simple use alone.
When to use this code
Use this code when the provider documents hallucinogen use and an induced disorder, but neither the substance nor the disorder type is specified. It is appropriate for incomplete records, emergency visits, or follow-up notes where detail is limited. Check documentation before assigning it.
Do not use for
Do not use this code for documented use of a specific hallucinogen when a more precise code is available. Do not use it for intoxication, dependence, abuse, or non-substance psychiatric conditions without a hallucinogen-induced disorder.
Coding tip
If the substance or induced disorder is named anywhere in the chart, code the more specific ICD-10-CM option instead of F16.99.