Major or Mild Neurocognitive Disorder Due to Alzheimer’s Disease 611
jury in a preschool child may also lead to significant developmental and learning issues.
Additional comorbidity of NCD is often relate d to the etiological subtype, as discussed in
the relevant sections. 
Major or Mild Neurocognitive Disorder
 Due to Alzheimer’s Disease
Diagnostic Criteria  
A. The criteria are met for major or mild neurocognitive disorder.
B. There is insidious onset and gradual progression of impairment in one or more cognitive
domains (for major neurocognitive disorder, at least two domains must be impaired).
C. Criteria are met for either probable or possible Alzheimer’s disease as follows:
For major neurocognitive disorder:
Probable Alzheimer’s disease is diagnosed if either of the following is present; oth-
erwise, possible Alzheimer’s disease  should be diagnosed.
1. Evidence of a causative Alzheimer’s disease genetic mutation from family history
or genetic testing. 
2. All three of the following are present:
a. Clear evidence of decline in memory and learning and at least one other cogni-
tive domain (based on detailed history or serial neuropsychological testing).
b. Steadily progressive, gradual decline in cognition, without extended plateaus.
c. No evidence of mixed etiology (i.e., absence of other neurodegenerative or
cerebrovascular disease, or another neurological, mental, or systemic disease
or condition likely contributing to cognitive decline).
For mild neurocognitive disorder:
Probable Alzheimer’s disease  is diagnosed if there is evidence of a causative Alz-
heimer’s disease genetic mutation from either genetic testing or family history.
Possible Alzheimer’s disease  is diagnosed if there is no evidence of a causative Alz-
heimer’s disease genetic mutation from either genetic testing or family history, and all