You gave it a pet name. It knows more about you than your mother does. Sometimes you even sleep with it. In fact, you're so attached to it that being separated for only a few minutes could send you into a panic.

While smartphone users worry about mobile hacking and other security threats that are making news these days, psychologists and others are concerned about another equally troubling issue: the growing obsession among people who would much rather interact with their phones than other humans.

"Watching people who get their first smartphone, there's a very quick progression from having a basic phone you don't talk about to people who love theiriPhone, name their phone and buy their phones outfits," said Lisa Merlo, director of psychotherapy training at the University of Florida.

Michelle Hackman, a recent high school graduate in Long Island, NY, won a $75,000 prize in this year's IntelScience Talent Search with a project investigating teens' attachment to their phones. She found that students separated from their phones were under-stimulated — a low heart rate was an indicator — and lacked the ability to entertain themselves.

For some, the anxious feeling that they might miss something has caused them to slumber next to their phones.

More than a third of U.S. adults — 35 percent — now own a smartphone, according to the Pew Research Center, and two-thirds of them sleep with their phones right next to their beds.

Michael Breus, a psychologist and sleep specialist, said in his patients often describe how they email and surf the Web as they're trying to wind down at night. He says this is a bad idea.

"This behavior can increase cognitive arousal," he says, "leading to the No. 1 complaint I hear: 'I can't turn off my mind and fall asleep.'"

Consumers' dependence on mobile phones is only expected to grow as people use their phones for things like shopping and banking.