TODAY | May 17, 2013
>>> in florida . now she's opening up about where she's been and her decision to leave behind her young family. here's nbc's anna navaz.
>> reporter: for years, brenda heist's family could only wonder what happened to her.
>> i thought probably after about two years i thought based on some of the information that she had been carjacked.
>> reporter: in 2002 the pennsylvania mom dropped off her kids at school and disappeared. daughter morgan was just 8-year-old, son lee was 12. brenda 's husband, lee, was a suspect and cleared.
>> my brother graduated from high school and college and i graduated and she wasn't there.
>> reporter: after seven years missing brenda heist was declared legally dead .
>> this is a rare situation, it truly is because to go off the radar, that completely for an adult is very difficult.
>> reporter: until two weeks ago, when the 54-year-old reappeared, a shadow of her former self.
>> i just kept saying to myself they're better off without me.
>> reporter: and broke her silence in an exclusive interview with dr. phil mcgraw .
>> her marriage was falling apart, her finances were falling apart, her future looked bleak.
>> reporter: mcgraw says heist now in a florida jail on outstanding warrants became overwhelmed and ran. she hitchhiked south and spent years living on the streets.
>> i've never been around homeless people at all, never knew anything about it, that's why i had my own problems believing what i was doing.
>> reporter: what she did was create a completely new life in florida , new identity, odd jobs, even new relationships, hundreds of miles away from the life she left behind .
>> she had 20 bucks in an empty purse and off she went for 11 years. you have to have a substantial level of mental and emotional maladjustment in order for this to look like a viable option to you.
>> reporter: heist has yet to face her children.
>> i don't want her to miss me and tell her she loves me. i don't want a sob story. i want the cold, hard truth.
>> do you want their forgiveness.
>> i would like my forgiveness but i'm going to have a hard time forgiving myself for what i've done.
>> reporter: former husband lee has moved on.
>> i just wish her that she'll get well, whatever the problems are.
>> reporter: problems that prompted her to finally turn herself in to authorities.
>> she just had hit bottom, bottom, bottom, so she just surrendered herself to the reality to stop the lies.
>> reporter: for "today," anna navaz, nbc news, los angeles .