id="article-body" class="row " section="article-body" data-component="trackCWV"> Many popular gaming apps -- this is GSN Casino Slots -- draw their look and casino slots feel from slot machines, blackjack tables and the like. Game Show Network

Many worries about the future weigh on Brett as he works his way through a gambling addiction program.

The 21-year-old's biggest worry after his release from the three-month program in California: encountering people, places and things that might trigger his urge to gamble.

But they're nothing compared with the biggest threat he'll face: his smartphone, and the many casino-style games available with a quick tap at an app store.

"I don't even have to go to a casino," said the former business student who asked to remain anonymous because of the stigma associated with his struggles.