Adeles drinking problem is revealed in Marc Shapiros book titled Adele, The Biography.
He details a time when her drinking left her visibly intoxicated while performing onstage. According to InTouch, Adele told Shapiro in an interview, I got so drunk by the time I went on at 2 a.m. I had forgotten the words to my own songs ... It was the worst thing ever. He says it all went down midway through her first tour.