Kendall Jenner and Kim Kardashian West Reveal Struggle With Anxiety

— -- Sisters Kim Kardashian West and Kendall Jenner opened up about their struggles with anxiety on the latest episode of "Keeping Up With the Kardashians."

Jenner, 21, confessed to her mom, Kris Jenner, that she was afraid to fall asleep because she believed she has a condition called sleep paralysis. People who suffer from sleep paralysis are temporarily unable to move or speak while falling asleep or waking up, but the mind is completely awake.

"I'm freaking out because recently I wake up in the middle of the night and I can't move," Kendall Jenner told her mom on Sunday's episode. "I'm scared to fall asleep because it keeps happening to me. It almost feels like my heart stops."

When Jenner explained that the problem occurs mostly on planes, Kris suggested that the problem stemmed from her daughter's "incredible anxiety about traveling."

Frustrated, Jenner responded, "But it's not...no I'm done arguing with people because everyone says I'm fine, but I don't feel fine. And I promise you one day when I'm rushed to the hospital then you guys are gonna wake up."

Kris reassured her daughter that she believed her but added, "The nature of what you do for a living and your career is flying around the world. You have designers that have already booked you and are counting on you to show up."

Kendall snapped back that her health is more important than her career.

Later, she reached out to sister Kim Kardashian West, who admitted that she too was suffering from anxiety (this was before the Paris robbery in October) -- whenever she got behind the wheel of a car.

The two then met with a therapist who offered to help them work through their anxiety by mimicking their symptoms. Jenner passed but Kardashian West agreed and went for a drive using some of the coping mechanisms the therapist taught her.

Still looking for a way to help her sister, Kardashian West invited Jenner over for a meditation class on her lawn. The meditation session seemed to work with Jenner calling it "pretty amazing."