John Mulaney opens up about drug addiction and recovery

In the latest episode of My Next Guest with David Letterman, the comedian opened up about his recovery from drug and alcohol addiction. During the interview, the host asked John about his experience in rehab. "It's not immediately great nights of sleep and serenity. I had zero gratitude. The actual detox from drugs was very physically uncomfortable, and I'd been on a lot of benzodiazepine like Xanax and Klonopin. Getting off those can be very rough. I was in the detox hospital room and I was grinding my teeth so much that a molar cracked."