F16.121Hallucinogen abuse with intoxication with delirium

F16.121 is the ICD-10-CM diagnosis code for hallucinogen abuse with intoxication with delirium. It belongs to category F16 (hallucinogen related disorders), block F10-F19 (mental and behavioral disorders due to psychoactive substance use) and chapter 5 (mental, Behavioral and Neurodevelopmental disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within F16.12 (hallucinogen abuse with intoxication), F16.121 is specifically for hallucinogen abuse with intoxication with delirium. Related codes cover uncomplicated (F16.120), with perceptual disturbance (F16.122) and unspecified (F16.129).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 894 (Alcohol, Drug Abuse or Dependence, Left AMA, relative weight 0.6275), DRG 895 (Alcohol, Drug Abuse or Dependence with Rehabilitation Therapy, relative weight 1.4266), DRG 896 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy with MCC, relative weight 1.6617) and DRG 897 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy without MCC, relative weight 0.8584), in MDC 20 (Alcohol/Drug Use and Alcohol/Drug Induced Organic Mental Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 292.81 (drug-induced delirium).