To me, I think it is a combination of a lot of things.
Lisa admits that she has spent most of her life trying to "please" people, probably everyone from her parents to the people she worked with on "Facts" to her husband. Lisa doesn't probably, herself, truly know or understand the true Lisa.
Then, when she left the show, she tried really hard to leave the Hollywood life behind. For someone that was as much a "child star" as she had been at that time, that probably meant going into an
isolation of sorts. In order to escape the lights and the lifestyle, she had to completely leave everything had had previously defined her behind, and try to remake herself at only 21.
Finally she goes through a nasty divorce. Now, again, everything she thought she had figured out about the "true Lisa" is shaken again. She had invested so much of herself into WIFE and MOM and now that is gone as well (she is still MOM but the perfect home life she had built for herself is gone now).
So now, she is still trying to figure out who she is, and to a great extent, she leans on her faith to help her do this. And in seeking to further her journey of self-exploration, she decides to go on Survivor (still scratching
my head over this one). Now she has to face all her inner demons, her desire to please everyone around her, her inability to compete in the game, etc. Probably extremely troubling for her. I think she did start to pull it together at the end (just in time to blindside Malcolm
), but not till after her brother arrived.
Also interesting to reflect that when it was time for "family" to visit, it wasn't one of her three children (ages 20-21-22) but her younger brother whom she most wished to see. I adore my brother, but if I were stuck on an island for 39 days and got to pick one person to see, it would definitely be one of my kids.