2026 ICD-10-CM Diagnosis Code F16.91Hallucinogen use, unspecified, in remission

ICD-10-CM Codes›F01–F99›F10-F19›F16

ICD-10-CM F16.91
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F16.91 is a billable ICD-10-CM diagnosis code for hallucinogen use, unspecified, in remission. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 894 through 897. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Mental and substance use disorders in remission.

Code Identity

ICD-10-CM Code
F16.91
Billable Status
Yes — Valid for Submission
Code Describes
Hallucinogen use, unspecified, in remission
Short Description
Hallucinogen use, unspecified, in remission
Same as the full description in the CMS dataset.
Parent Code
F16.9
Hallucinogen use, unspecified

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF10-F19Mental and behavioral disorders due to psychoactive substance use
CategoryF16Hallucinogen related disorders
This CodeF16.91Hallucinogen use, unspecified, in remission

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Use(of)
      • hallucinogen NEC
        • in remission

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MBD026
Mental and substance use disorders in remission
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement F16.91 replaces the following previously assigned code(s):

  • F16.90 - Hallucinogen use, unspecified, uncomplicated
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F16.91Overview

Is F16.91 (Hallucinogen use, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report hallucinogen use, unspecified, in remission on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does F16.91 group to?

When hallucinogen use, unspecified, in remission is the principal diagnosis on an inpatient stay, it groups to MS-DRG 894, 895, 896, 897, with relative weights from 0.6169 to 1.7451 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.