624 Neurocognitive Disorders
Other mental disorders. A diagnosis of major or mild vascular NCD is inappropriate if
the symptoms can be entirely attributed to  delirium, although delirium may sometimes be
superimposed on a preexisting major or mild vascular NCD, in which case both diagnoses
can be made. If the criteria for major depressive disorder are met and the cognitive impair-
ment is temporally related to the likely onse t of the depression, major or mild vascular
NCD should not be diagnosed. However, if the NCD preceded the development of the de-
pression, or the severity of the cognitive impairment is out of proportion to the severity of
the depression, both should be diagnosed. 
Comorbidity
Major or mild NCD due to Alzheimer’s dise ase commonly co-occurs with major or mild
vascular NCD, in which case both diagnoses should be made. Major or mild vascular NCD
and depression frequently co-occur. 
Major or Mild Neurocognitive Disorder
Due to Traumatic Brain Injury
Diagnostic Criteria  
A. The criteria are met for major or mild neurocognitive disorder.
B. There is evidence of a traumatic brain injury—that is, an impact to the head or other
mechanisms of rapid movement or displacement of the brain within the skull, with one
or more of the following: 
1. Loss of consciousness.
2. Posttraumatic amnesia.
3. Disorientation and confusion.
4. Neurological signs (e.g., neuroimaging demonstrating injury; a new onset of sei-
zures; a marked worsening of a preexisting seizure disorder; visual field cuts; an-
osmia; hemiparesis).
C. The neurocognitive disorder presents imm ediately after the occurrence of the trau-
matic brain injury or immediately after recovery of consciousness and persists past the