Lyric discussion by eje 

Cover art for Sister lyrics by City and Colour

This song is definitely not about drug addiction. I think its more about a mental illness ie depression or schizophrenia ("the whispering ghosts" and "what have the demons done"). The "pills they gave you" is talking about medication etc to help rather than drugs. Saw him at the royal albert hall recently and he played this song which was the first time Id heard it. Its absolutely breathtaking, and no matter what its about express's the pain and anguish felt by both Dallas and evidently his sister in a completely emotional way.

My Interpretation

i agree with eje. i do think this song is about depression and the struggle with non compatible pills. they can really mess yuo up if you are given the wrong stuff. this song connects with me so much, every performance he pours so much raw emotion into this particluar song.