Sarah says that she has a “lying addiction.” She admits that she has lied to friends and family about having cancer, a husband, a child, a stalker and muscular dystrophy. She says it’s a compulsion and she wants to figure out why she deceives everyone she meets.

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Dr. Phil explains to her the difference between an irresistible impulse and an impulse not resisted, and asks her which is the reason that she lies. Hear her answer in the video above.

WATCH: Woman Claims Former Friend Who Repeatedly Lied To Her Became Obsessed With Her

And, Dr. Phil explains to Liz, Brian and Bethany, former friends of Sarah who say they were duped by her, why he believes Sarah lacks empathy and is not remorseful.

On Monday, see what happens when a cancer survivor and former friend of Sarah confronts her for the first time. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Do you need Dr. Phil to "get real" with someone?

How A Woman’s Expressions While She Confesses To Lies Contradict Her Words – And What It Means