Diagnostic Criteria  
A. The criteria are met for major or mild neurocognitive disorder.
B. The disturbance occurs in the setting of established Parkinson’s disease.
C. There is insidious onset and gradual progression of impairment.
D. The neurocognitive disorder is not attribut able to another medical condition and is not
better explained by another mental disorder.
Major or mild neurocognitive disorder  probably due to Parkinson’s disease  should
be diagnosed if 1 and 2 are both met. Major or mild neurocognitive disorder possibly
due to Parkinson’s disease should be diagnosed if 1 or 2 is met:
1. There is no evidence of mixed etiology (i.e., absence of other neurodegenerative or
cerebrovascular disease or another neurological, mental, or systemic disease or con-
dition likely contributing to cognitive decline).
2. The Parkinson’s disease clearly precedes the onset of the neurocognitive disorder.
Coding note: For major neurocognitive disorder probably due to Parkinson’s disease,
with behavioral disturbance, code first 332.0 (G20)  Parkinson’s disease, followed by
294.11 (F02.81)  major neurocognitive disorder probably due to Parkinson’s disease, with
behavioral disturbance. For major neurocognitive disorder probably due to Parkinson’s
disease, without behavioral disturbance, code first 332.0 (G20)  Parkinson’s disease, fol-