Age magnified our quirks.  With an increase in seniority and a decrease in superiors, we gain more and more freedom to express our character flaws. This is one of the benefits of aging.

But how can you tell if these character flaws are borne of something physiological?  How do we know whether this is just eccentricity that naturally accompanies aging, or if these are early signs of Alzheimer's or Parkinson's?

A friend of mind had to stop her knife-weiding mother from stabbing someone.  That's a good sign. Does it have to come to that, though?