ICD-10-CM > S00-T88 > T36-T50 > T40 > T40.9 > T40.99 > T40.996 T40.996 Underdosing of other psychodysleptics [hallucinogens] Non-Billable/Non-Specific Codes T40.996A..., initial encounterT40.996D..., subsequent encounterT40.996S..., sequela