Leno began to drink heavily after performances, and, by 1901, like his father and stepfather before him, he had become an alcoholic. He gradually declined physically and mentally and displayed frequent bouts of erratic behaviour that began to affect his work. By 1902, Leno's angry and violent behaviour directed at fellow cast members, friends and family had become frequent. Once composed, he would become remorseful and apologetic. His erratic behaviour was often a result of his diminishing ability to remember his lines and inaudibility in performance. Leno also suffered increasing deafness, which eventually caused problems on and off stage. In 1901, during a production of "Bluebeard", Leno missed his verbal cue and, as a result, was left stuck up a tower for more than twenty minutes. At the end of the run of "Mother Goose" in 1903, producer Arthur Collins gave a tribute to Leno and presented him, on behalf of the Drury Lane Theatre's management, with an expensive silver dinner service. Leno rose to his feet and said: "Governor, it's a magnificent present! I congratulate you and you deserve it!"