I personally think this this song is about his girlfriend being a heroin addict.
"She's yelling on the phone, she's yelling on the phone again.
And she's banging on the door; she's losing all control again"
^Violent need for the drug
"What's she's doing in the tub?
She's shooting up the junk again."
^injecting heroin
"Demon with the needles leaning over your shoulder"
^her dealer controls her and her addictive need for the drug.
I personally think this this song is about his girlfriend being a heroin addict.
"She's yelling on the phone, she's yelling on the phone again. And she's banging on the door; she's losing all control again" ^Violent need for the drug
"What's she's doing in the tub? She's shooting up the junk again." ^injecting heroin
"Demon with the needles leaning over your shoulder" ^her dealer controls her and her addictive need for the drug.