Adderall (End of the Line) was just titled Adderall when it was released as a single days before the full Food for Worms album dropped. The parenthetical was only added to the title on all platforms after the album’s release.
In an Instagram post made after the song was added to BBC Radio 6’s A List, Shame suggest that the parenthetical was added for legal reasons:

If you’re wondering why we’ve had to change the name to End of the Line, just know that we haven’t gained the capital to take on Big Pharma in court yet but we’re working on it.

Whether adding words after the brand name in the title would prevent a lawsuit over it, or if the band are being serious in the first place, is still up for debate.