Elle says that her mother, Donna’s, focus on her older sister, Arielle’s, heroin dependency, left her feeling neglected in her own family. The teenager claims that the responsibility of taking care of Arielle’s child started when she was 14, which resulted in her feeling angry, annoyed, and tired.

“I felt like I wasn’t really that important and that my problems weren’t as important as Arielle’s,” says Elle. She claims that Donna also stopped helping their brother, Michael, who struggles with reading.

Donna and Ivy agree that Elle helped with feeding Arielle’s child, but deny that they left her responsible for parenting duties. However, they admit that they were unaware of how Elle felt.

Donna says that because she was focused on Arielle, she missed "a lot" of what was going on with her other children. “I was detached,” she admits. The children’s father, Ivy, says he “wasn’t aware” of how Elle felt about the situation at home.

And later, Donna says she believes it’s been over a year since Arielle last took heroin. How do she and Ivy respond when their 32-year-old daughter admits she used the drug just four to five weeks prior to meeting Dr. Phil?

Part one of this three-part Dr. Phil, “Running on Empty: A Broken Family, Part 1,” airs Monday. Check your local listing to find out where you can watch.

WATCH: ‘I Couldn’t Get Up And Tie My Shoe Without Putting A Needle In My Arm,’ Says Woman Who Battles Heroin Dependency

TELL DR. PHIL YOUR STORY: A family/relationship divided?