[Thoro]

I could have sworn that that particular episode was more of a spoof on an old ABC Afterschool Special that featured Ben Affleck as a steroid addicted high school athlete.

The Cartman angle was just a subplot.

I'm currently researching a link confirming it.

[Thoro]

"Affleck also starred in the 1994 HBO "Lifestories: Families in Crisis" installment, "Body to Die For: The Aaron Henry Story" about a teen whose life is imperiled when he becomes addicted to steroids."

Found it here, and a conversation about it here. Like I said, it's pretty much a scene for scene spoof. The Cartman subplot pretty much writes itself once Jimmy replaces Ben Affleck.