Lyric discussion by pavirusco 

Cover art for Trouble lyrics by Isobel Campbell and Mark Lanegan

I always thought the lyrics were "Haven't slept a day in years" instead of "Haven't slipped".

Might be my own sleep deprivation though ;-)

Anyway, can someone explain to me what "Haven't slipped a day in years" would mean? English isn't my first language so I might miss something here.

I would have to say that "Haven't slipped a day in years" is referring to Mark Lanegan's struggle with drug addiction and that he hasn't resorted to using drugs in years or slipped in years.