Additional comorbidity of NCD is often related to the etiological subtype, as discussed in the relevant sections.
Due to Alzheimer’s Disease
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 three of the following are present: 1. Clear evidence of decline in memory and learning.
2. Steadily progressive, gradual decline in cognition, without extended plateaus.
3. No evidence of mixed etiology (i.e., absence of other neurodegenerative or cere- brovascular disease, or another neurological or systemic disease or condition likely contributing to cognitive decline).
D. The disturbance is not better explained by cerebrovascular disease. another neurode- generative disease, the effects of a substance, or another mental, neurological, or sys- temic disorder.
Coding note: For probable major neurocognitive disorder due to Alzheimer‘s disease, with behavioral disturbance, code first 331.0 (G303) Alzheimer‘s disease, followed by 294.11 (F02.81) major neurocognitive disorder due to Alzheimer’s disease. For probable neurocognitive disorder due to Alzheimer's disease, without behavioral disturbance, code first 331.0 (G309) Alzheimer's disease, followed by 294.10 (F02.80) major neurocognitive disorder due to Alzheimer's disease. without behavioral disturbance.
For possible major neurocognitive disorder due to Alzheimer’s disease, code 331.9 (G31.9) possible major neurocognitive disorder due to Alzheimer‘s disease. (Note: Do not use the additional code for Alzheimer’s disease. Behavioral disturbance cannot be coded but should still be indicated in writing.)
For mild neurocognitive disorder due to Alzheimer’s disease, code 331.83 (G31.84).
(Note: Do not use the additional code for Alzheimer’s disease. Behavioral disturbance cannot be coded but should still be indicated in writing.)