Newton's Behavioral Shift

I found it particularly interesting that the movie we watched identified a number of distinct changes in Newton's social behavior and political involvement.  If I'm not mistaken, these changes took place shortly after his mysterious illness.  Apparently, Newton was very reclusive prior to the illness and at some point after recovering from it he became much more social, became involved in politics and even exhibited his newfound societal consciousness by commissioning as many as 14 portraits of himself.  I wonder if there is any specific realization or other cause for this change in behavior that Newton experienced which can be discerned more specifically.  Also, the movie didn't really seem to specify as to whether this change in behavior continued for the remainder of Newton's life or whether there was a certain point at which he once again retreated into relative seclusion.