NEW YORK – 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 smartphones than with other human beings.

"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 their iPhone, name their phone and buy their phones outfits," said Lisa Merlo, director of psychotherapy training at the University of Florida.

The increasing dependence comes as more Americans ditch their iPods, cameras, maps and address books in favor of the myriad capabilities of a smartphone. After all, companies have rolled out thousands of applications that do everything from track your heart rate to guide you through the streets of New York City. While smartphones have made life easier for some, psychologists say the love of them is becoming more like an addiction, creating consequences that range from minor (teenagers who communicate in three-letter acronyms like LOL and BRB) to major (car accidents caused by people who text while driving).

Merlo, a clinical psychologist, said she's observed a number of behaviors among smartphone users that she labels "problematic." Among them, Merlo says some patients pretend to talk on the phone or fiddle with apps to avoid eye contact or other interactions at a bar or a party. Others are so genuinely engrossed in their phones that they ignore the people around them completely.

"The more bells and whistles the phone has," she says, "the more likely they are to get too attached."

Michelle Hackman, a recent high school graduate in Long Island, NY, won a $75,000 prize in this year's Intel Science Talent Search with a research project investigating teens' attachment to their cell 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.

Most of the teens at Hackman's affluent high school own smartphones, she says, and could even be found texting under their desks during class. "It creates an on-edge feeling and you don't realize how much of the lecture you're missing," Hackman says.

For some, the anxious feeling that they might miss something has caused them to slumber next to their smartphones. 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 clinical practice, his patients often describe how they answer emails, text 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'."

Trouble sleeping isn't the only problem smartphones junkies exhibit. Some people are willing to do almost anything to feed their addiction —— including spending more money for the data plans than they can afford. According to J.D. Power and Associates, the average smartphone user spends about $107 each month for wireless access —— more than the average household pays for electricity each month.

And consumers' dependence on mobile phones is only expected to grow as people use their phones for things like shopping and banking. Mobile commerce — purchases made when shoppers access stores' websites or mobile applications through their phones — is expected to account for $6 billion in sales this year, according to Forrester Research.

For instance, Kristyn Wilson, a marketing professional in Columbus, Ohio, uses her phone to locate stores and compare prices, in addition to ordinary tasks like checking email and sending texts. She also uses it to buy entertainment vouchers through daily deal site Groupon and even to pay for her coffee at Starbucks, where she simply has to wave the phone in front of a scanner. As a result, she rarely separates from the device.

"My phone is in my hand all the time," says Wilson, who stops short of sleeping next to her phone. "You have to draw the line somewhere."

For others, being away from their phone will almost certainly cause separation anxiety. According to researchers at the Ericsson ConsumerLab, some people have become so dependent on being able to use their smartphones to go online anytime, anywhere, that without that access, they "can no longer handle their daily routine."

Keosha Harvey, a party booker in Burlington, NC, can attest to that. She uses her iPhone for both personal and business communications, so she panicked when it crashed earlier this month, taking all of her "important contacts" with it. Apple replaced it for free, but she lost her pictures and more than 400 songs, she says.

"The most frustrating part is that lost feeling you get when you are so used to having a phone," says Harvey, who also has had Blackberry devices "go dead" on her in the past. "You feel a sense of nakedness without it."

Tonia Zampieri lost her iPhone in a cab on New Year's Eve while on vacation in Washington D.C. Having paid her fare with cash, she had no way of tracking down the cab company, and her older-model phone didn't have the tracking software that comes standard now. She had backed up her contacts on her computer six weeks earlier, but she lost other data, including videos of her niece.

The worst part, Zampieri says, was the feeling of being cut off.

"I was without a phone for four days, and it was excruciating. I kept going to look for it but then I'd be like, 'I don't have it. That's right,'" Zampieri says. "It's definitely a borderline addiction for me."