"Self-spoiled" - where did term come from?

Theoretically, of course, kids CAN'T spoil themselves - only adults can
spoil them. However, I've heard the term used, so I wonder how it came
about and how you would define it. I suppose the idea is that since we
are all born self-centered, there are always some kids who manage to
hang on to their narcissism (with the help of movies and TV) despite
all the efforts of parents to pull them away from that mindset. One
example of that might be the comic strip "Stone Soup," which stars Val,
a hardworking, frugal, egalitarian mother, but whose daughter Holly is
very much the lazy, materialistic, vain princess whose attitude towards
getting a boyfriend is based on acting (in her mother's sarcastic
terms) "helpless but equal". (Granted, you don't see Val taking the
hard line with Holly that often - but she doesn't "indulge" her
either.)

I'd probably define the term as describing those whose parents made
them work a lot and who had just enough low-tech toys not to weaken
their imaginations, but who didn't appreciate their parents'
moderateness, resented being "different" from other families, and so
drowned themselves in TV and learned to feel sorry for themselves,
watching nothing but shows about rich kids - and shows like "Friends"
where no one seems to work for a living. Or something like that.

So, etymologically speaking (and otherwise), how, when and where did
the term start being used, to your knowledge? Thanks.

Lenona.