Osbourne's drug and alcohol misuse have at times caused friction within his band. Don Airey, keyboardist for Osbourne during his early solo career, has said that the vocalist's substance-misuse issues were what ultimately caused him to leave the band. In his memoir "Off the Rails", former bassist Rudy Sarzo detailed the frustrations felt by him and his bandmates as they coped with life on the road with the vocalist, who was in a state of near-constant inebriation and was often so hungover that he would refuse to perform. When he was able to perform, his voice was often so damaged from cigarettes and alcohol that the performance suffered. Many shows on the American leg of the 1981-82 "Diary of a Madman" tour were simply cancelled, and the members of his band quickly began to tire of the unpredictability, coupled with the often violent mood swings he was prone to when drunk.