CDC Proposal for New ICD11 Code for combined Cannabis Induced Vomiting and Delirium

 

Proposal to Add a New ICD-11 Category: Cannabis-Induced Hyperemesis With Delirium

Submitted to:

Centers for Disease Control and Prevention (CDC)
National Center for Health Statistics (NCHS)
ICD Coordination and Maintenance Committee

Date: November 10, 2025

1. Proposal Summary

This proposal requests creation of a new ICD-11 category under Disorders due to use of cannabis (6C41) to capture the co-occurrence of cannabis-induced hyperemesis and delirium as a distinct clinical entity. The proposed code would enable accurate epidemiologic tracking of neuro-gastrointestinal toxicity from tetrahydrocannabinol (THC) exposure, particularly among older adults users consuming high-dose edible or combined oral/inhaled cannabis products.

2. Proposed New Entity

Proposed Title: 6C41.Y — Cannabis-Induced Hyperemesis With Delirium

Parent Category: 6C41 — Disorders due to use of cannabis

Proposed Type: New distinct entity (combination disorder)

Synonyms: Concurrent cannabis-induced hyperemesis and delirium; THC toxicity with vomiting and delirium; Cannabis-related hyperemesis-delirium complex.

3. Rationale for Inclusion

Both cannabis-induced hyperemesis syndrome (CHS) and cannabis-induced delirium are recognized in ICD-11, yet clinical reports increasingly demonstrate that these conditions can occur simultaneously. This co-occurrence represents a distinct pathophysiologic syndrome characterized by severe vomiting, dehydration, and altered mental status linked to THC toxicity. The current ICD-11 structure requires dual coding (6C41.5 and MD90.1), which hampers accurate reporting and surveillance.

Clinically, CHS and delirium share overlapping etiologic factors—THC accumulation, dehydration, metabolic stress, and age-related pharmacodynamic sensitivity. Older adults and new cannabis users represent an emerging risk population with unique vulnerability to combined neuro-gastrointestinal toxicity.

4. Epidemiologic Relevance

Cannabis-induced hyperemesis syndrome is increasingly reported globally with legalization and higher potency formulations. Delirium due to cannabis toxicity, though rare, is documented particularly among elderly users or those ingesting edibles. The overlap of both syndromes in one episode, though underreported, likely contributes to emergency department visits labeled as 'nausea and confusion after cannabis use'. A unique code would improve public health surveillance and facilitate research into THC-related systemic and neuropsychiatric complications.

5. Case Example (Index Case)

A 75-year-old woman ingested 40 mg of oral THC and smoked cannabis the same day, developing repeated vomiting of green bile followed by expressive aphasia, disorientation, and confusion lasting 36 hours. She was mildly dehydrated but otherwise stable. Both hyperemesis and delirium resolved after intravenous fluids and observation. No structural or metabolic cause was found. (Behar D. Concurrent Cannabis-Induced Hyperemesis and Delirium in an Older Adult: Case Report, 2025.)

6. Proposed ICD-11 Structure

Code: 6C41.Y — Cannabis-Induced Hyperemesis With Delirium
Description: A disorder characterized by the simultaneous occurrence of severe nausea and vomiting (hyperemesis) and an acute confusional or delirious state, temporally related to cannabis use. Symptoms typically resolve after cessation of cannabis and supportive therapy.

Hierarchical placement:
→ 6C4 — Mental and behavioural disorders due to psychoactive substance use
→ 6C41 — Disorders due to use of cannabis
→ 6C41.Y — Cannabis-Induced Hyperemesis With Delirium

Exclusions:
- 6C41.5 Cannabis-induced delirium (without vomiting)
- MD90.1 Vomiting, unspecified
- 8A80.4 Cyclic vomiting syndrome

7. Supporting Evidence

1.       Allen JH, de Moore GM, Heddle R, Twartz JC. Cannabinoid hyperemesis: cyclical hyperemesis in association with chronic cannabis abuse. Gut. 2004;53(11):1566–1570.

2.       Lapoint J, Meyer S, Yu CK, Koenig KL, Thihalolipavan S, Anderson IB. Cannabinoid hyperemesis syndrome: public health implications and a novel model treatment guideline. West J Emerg Med. 2018;19(2):380–386.

3.       Sorensen CJ, DeSanto K, Borgelt L, Phillips KT, Monte AA. Cannabinoid hyperemesis syndrome: diagnosis, pathophysiology, and treatment—a systematic review. J Med Toxicol. 2017;13(1):71–87.

4.       Hall W, Degenhardt L. Adverse health effects of non-medical cannabis use. Lancet. 2009;374(9698):1383–1391.

5.       Stark T, Pettit A, Nystrom K, Hall J. Delirium following ingestion of cannabis edibles in an elderly patient: a case report. Clin Gerontol. 2020;43(8):123–129.

8. Public Health and Policy Impact

• Improved surveillance: Enables tracking of combined neuropsychiatric and gastrointestinal toxicity linked to cannabis.
• Enhanced clinical recognition: Encourages integrated management of delirium and hyperemesis as a unified syndrome.
• Geriatric safety: Identifies a vulnerable subgroup at risk from oral and combined THC formulations.
• Research facilitation: Supports pharmacovigilance, outcomes tracking, and coding consistency across datasets.

9. Requested Action

The CDC/NCHS and WHO-FIC Update Committee are requested to:
1. Approve creation of ICD-11 code 6C41.Y — Cannabis-Induced Hyperemesis With Delirium.
2. Include the entity in the ICD-11 2026 Update Cycle.
3. Issue coding guidance to emergency medicine, psychiatry, and toxicology providers.