Stacey says ever since high school, her younger sister, Courtney’s, lying has escalated. She claims Courtney lies about everything from stealing to being pregnant, and that their entire family is suffering.

TELL DR. PHIL YOUR STORY: Know someone with outrageous behavior?

In the video above, Dr. Phil reviews some of the lies Stacey claims Courtney has told, including taking their mom’s iPad and blaming it on Stacey’s son, stealing Stacey’s license and getting arrested landing Stacey in jail, and faking three pregnancies – all which Stacey says Courtney blames on her mental illness.

WATCH: Why Parents Say They Are ‘Completely At Our Wits’ End’ With 27-Year-Old Daughter

On Monday, hear how Courtney explains her behavior. And, see what happens that causes her to walk off stage. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Ready to confront someone?

Woman Says She Doesn’t Mean To Steal, ‘It’s Just A Part Of My Mental Illness’