It’s been five years since Eminem’s last album. In hip-hop terms, we might as well be talking about an entire generation. There are certainly parts of Relapse, his fifth CD, where it seems like he was in a coma for the past half-decade. That may not be too far from the truth, since the record’s best cuts are about the rapper’s addiction to prescription pills and the zombie-like climb he took out of hell to get back among the land of the living. The album begins with a 90-second skit in which a rehab doctor advises Em to “take a drink [to] take the edge off.” Much of Relapse is about the artist’s battle to stay sober in a world that likes him best when he’s fucked up. So we have cuts about Eminem walking around in a daze (“3 a.m.”), being abused by his stepfather (“Insane”) and hiding pills around the house (“Déjà Vu”). Dr. Dre’s spare, spooky production provides Relapse with an appropriate air of dread. But almost half of the album falls back on Eminem’s usual shock rhymes: Rape, murder and blaming Mom for his problems all get moments in the spotlight. And the record’s single, “We Made You,” takes swipes at celebs who haven’t mattered since the last time Eminem released an album. His shady past may inform Relapse, but Em sounds most persuasive when he’s hoping for a sober future.