Lee was in his twenties when he first experimented with drugs, trying marijuana and cocaine while studying abroad in the U.S. But he says that when he returned to South Korea, he started using “stronger” stuff.

“At first, it was occasional. But once a month became once a week… and then I started using every day. I wanted to quit, but I just couldn’t stop,” said Lee, a pseudonym he uses as a recovering addict in Narcotics Anonymous. “Then one day, I was arrested.”

Lee’s arrest eight years ago makes him one of the tens of thousands of South Koreans