A person with obsessive-compulsive disorder, or O.C.D., is plagued by recurrent, unwanted thoughts and repetitive behaviors like hand-washing or counting. The first symptoms usually occur in childhood, and O.C.D. is said to afflict more than two million adults in the United States, according to the National Institute of Mental Health.

This week, the Patient Voices series by New York Times producer Karen Barrow focuses on six men and women with O.C.D.

Jared Kant, 26, of Boston, said the anxiety of O.C.D. often doesn’t make sense to those who witness it.

“That’s the torture of the disorder,” Mr. Kant says. “You’re totally cognizant that the things that you’re afraid of are not rational. But the fact that they’re not rational, that you know they’re not rational, doesn’t make them any less terrifying.”

Listen to more Voices of O.C.D., including a man who didn’t realize he had the condition until he was 50 and a high school student who battles his own “O.C.D. bully.”

After listening, please join the discussion below. Have you or someone you know experienced obsessive-compulsive disorder? Tell us about it.