628 Neurocognitive Disorders
E. The neurocognitive disorder is not attributable to another medical condition or is not
better explained by another mental disorder.
Coding note:  The ICD-9-CM and ICD-10-CM codes for the [specific substance/medica-
tion]-induced neurocognitive disorders are indi cated in the table below. Note that the ICD-
10-CM code depends on whether or not there is a comorbid substance use disorder present
for the same class of substance. If a mild substance use disorder is comorbid with the sub-
stance-induced neurocognitive disorder, the 4th position character is “1,” and the clinician
should record “mild [substance] use disorder” before the substance-induced neurocognitive
disorder (e.g., “mild inhalant use disorder wi th inhalant-induced major neurocognitive disor-
der”). If a moderate or severe  substance use disorder is comorbid with the substance-
induced neurocognitive disorder, the 4th position character is “2,” and the clinician should
record “moderate [substance] use disorder” or “severe [substance] use disorder,” depending
on the severity of the comorbid substance use disorder. If there is no comorbid substance
use disorder, then the 4th position character is “9,” and the clinician should record only the
substance-induced neurocognitive disorder. For some classes of substances (i.e., alcohol;
sedatives, hypnotics, anxiolytics), it is not permissible to code a comorbid mild substance
use disorder with a substance-induced neurocog nitive disorder; only a comorbid moderate
or severe substance use disorder, or no substance use disorder, can be diagnosed. Behav-