 Alice in Chains is also noted for the unique vocal harmonies of Staley ( or DuVall ) and Cantrell , which included overlapping passages , dual lead vocals , and trademark harmonies typically separated by a major third . Alyssa Burrows said the band 's distinctive sound " came from Staley 's vocal style and his lyrics dealing with personal struggles and addiction " . Staley 's songs were often considered " dark " , with themes such as drug abuse , depression , and suicide , while Cantrell 's lyrics often dealt with personal relationships . 
