Originally posted by Gordonator:
rumours has it that she regretted starring in an adult film. the
stress led to depression which in turn led to the tragedy.

In case some might misunderstand, "Juhong Geulshi (The Scarlet
Letter)" wasn't actually an adult film. Well, at least not in the
AV sense. 
Lee played a lonely lounge singer who was the mistress of a police
detective. There are a few steamy love scenes in which she did bare
all, but thanks to the clever camera angles, audience don't get to
see anything revealing.
According to interviews from her family and close friends, the
sensitive Lee did undergo some form of depression due to public
scrutiny over the daring scenes in the movie, but it was not her
first time (though it was her most daring effort) doing love scenes
for a movie anyway. Besides, her fame had already been on the rise
since her appearance in the blockbuster hit "Tae Guk Gi:
Brotherhood" and with other projects in the pipeline, she had
finally attained her objective -- to be treated as a serious actor
and not as a bubblegum idol.
That was why some friends speculated that her family problems could
have been the cause of her depression as well. Too bad her farewell
note didn't shed much light on the reasons behind her
decision.
Whatever it is, her departure is a great loss to the Korean movie
industry. And a grave reminder to all that beauty and fame does not
necssarily buy one happiness.