Related : Why MTV's "The Challenge" Stars Keep Coming Back

"It's like a drug."

Obsessed with MTV's The Challenge? So are its competitors, who can't resist returning to one of the longest running reality competitions on TV, debuting in 1998. Over the years, the show has produced some of reality TV's most well-known stars.

So what keeps some of these fan-favorites coming back for the insane physical challenges and partying each year? For some, it's all about the family unit they've created over the years.

"I just took a couple of years off and I missed it, my dysfunctional family that I live with abroad," Chris "CT" Tamburello, who recently became a father, coming off of his big win on The Challenge: Invasion of the Champs, told E! News.

Camila Nakagawa added, "At the end of the day, we're all a really screwed up family, so we can say that we hate each other, but we miss each other whenever we're not together."