According to mental health professionals like Dr. David Greenfield, Director of the Center for Internet and Technology Addiction, smart phone addiction is real. In fact, he estimates that 90 percent of Americans probably fall into the "overusing or abusing" category when it comes to their smart phones. He reached this conclusion following a 2014 telephone survey of 1,000 smart phone users, conducted in conjunction with AT&T. But those aren't true addicts -- just misusers, he says. So how can you tell if you're actually addicted to your phone?