I'll take a few seconds to answer before giving the floor to Dr. Andrew.
These days, patients who receive a diagnosis of a neurodegenerative disease or dementia can get it as long as they still have decision-making capacity. Why? Because they are asking why they are experiencing judgment, memory, and other problems. So they consult their doctor, who makes a diagnosis.
Some patients are definitely capable of deciding, just like people who are perfectly capable of driving their car and going about their business.
I believe that a diagnosis is essential. There is no contraindication.
I will now give the floor to Dr. Andrew.