Shit, where the fuck you think I picked up the habit
All I had to do was go in her room and lift up her mattress

from Eminem – Marshall Mathers Lyrics on Rap Genius

Meaning

Dan Carlisle, a fellow Detroit MC who performed under the name Hush, has commented on this line to The Detroit Metro Times:

When Em got back from LA recording The Slim Shady LP […] we went to his mother’s house in the trailer park on 26 Mile. His mom tried to be nice, but she didn’t look so good. I’d been forewarned by Em, but it was a bit of shock to see her so blew out,” says Hush. “But then the first thing Em does is lift up her mattress and look for pills. When he says ‘I picked up the habit’ on The Marshall Mathers LP, he means it.

From the same article linked above, DJ Rec (Bob Claus), Em’s onetime roommate who produced The Slim Shady EP versions of “Murder, Murder” and “If I Had…” as well as the original “My Name Is”, explains:

[Eminem] was straight-edge back in the day. He could hardly take a hit of a joint. He messed around with the painkillers every once in a while — especially when they’re literally laying around the house.

Eminem would later devote an entire song (“My Mom”) to claiming that his mother forced him to take valiums and other drugs and thus started his lifelong pattern of drug abuse

To help improve the meaning of these lyrics, visit “Marshall Mathers” by Eminem Lyrics and leave a comment on the lyrics box