Shelby and Shayne lost their sister, Kelsey, to a drug overdose in 2011. Today, both women admit they, too, have struggled with drug dependency for years.

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Shelby says her drug use “took off” right after Kelsey’s death, though she says she’s been clean for 6 months, and Shayne, who is currently using, claims that getting high is the only thing that helps her to not think about Kelsey.

WATCH: Dr. Phil To Guest With Anxiety And Depression: ‘That Has To Be Dealt With’

At first, Shelby declines Dr. Phil’s referral to the PNP Center for a complete neurological and biochemical evaluation, then later reconsiders and accepts the offer of help, saying, “I really didn’t mean to shut you down so quick.”

Turning to Shayne, Dr. Phil says, “Your life is on the line.”

When he refers her first to Revive Treatment Center, to help get her off the drugs, and then to Awakenings Treatment Center to address her emotional and dependency issues, does Shayne agree to go?

Watch the video above, then check here to find out where you can watch the conclusion of this two-part Dr. Phil airing Tuesday

TELL DR. PHIL YOUR STORY: Chaos in your life?