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ICD-10-CM 2027 diagnosis code

T40.906Underdosing of unspecified psychodysleptics [hallucinogens]

Not billable — use a more specific codeRequires 7th character

T40.906 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.

Code last changed in FY2020 (effective October 1, 2019). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T40.906

T40.906 is the ICD-10-CM diagnosis code for underdosing of unspecified psychodysleptics [hallucinogens]. It belongs to category T40 (poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]), block T36-T50 (poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within T40.90, choose T40.906 (Underdosing of unspecified psychodysleptics [hallucinogens]) only when documentation doesn't support a more specific option: poisoning by unspecified psychodysleptics [hallucinogens], accidental (unintentional) (T40.901), poisoning by unspecified psychodysleptics [hallucinogens], intentional self-harm (T40.902), poisoning by unspecified psychodysleptics [hallucinogens], assault (T40.903), poisoning by unspecified psychodysleptics [hallucinogens], undetermined (T40.904) and adverse effect of unspecified psychodysleptics [hallucinogens] (T40.905).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2020 (title revised).

7th character

The appropriate 7th character is to be added to each code from category T40

Notes that apply from higher levels

Instructions written at a parent level also apply to T40.906.

› From T40 Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
Excludes2
  • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.-F19.-)

Broader instructions also apply from T36-T50 Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances and Chapter 19: Injury, poisoning and certain other consequences of external causes.

Table of Drugs & Neoplasms entries

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • FY2020 (effective 10/1/2019): Title revised — was “Underdosing of unspecified psychodysleptics”

Common questions about T40.906

Is T40.906 billable?

No. T40.906 is a header code. Report one of its more specific subcodes instead.