They sleep with them under their pillows and take them into the bathroom. They snap photos, go online and push the limits of unlimited-texting plans.

They sleep with them under their pillows and take them into the bathroom. They snap photos, go online and push the limits of unlimited-texting plans.

American teens and their cell phones have become one.

"I broke mine and had to go without it for a few days," said Damika Dean, a senior at South High School. "I felt like I was on an island -- by myself."

A report released last month by the Pew Internet & American Life Project says that teens don't see the devices as mere phones. They are indispensable tools, used to share videos, listen to music and ring in place of alarm clocks. And, maybe most of all, cell phones mean being reachable -- 24 hours a day.

"Many teens said they slept with their phones," said Amanda Lenhart, a co-author of the report. "They felt there was an expectation that they would always be available."

About 75 percent of 12- to 17-year-olds own cell phones now, up from 45 percent in 2004, the Pew report says. About 72 percent of all teens are text-messagers, up from 51 percent in 2006.

A third of them send more than 100 texts a day; about 15 percent of teens who are texters top 6,000 a month.

Even the researchers gasped, Lenhart said.

"When we first saw the numbers on texting, I think we were a little surprised," she said. "The increase over the past 18 months is just tremendous."

Lenhart said the rise in unlimited-texting plans likely is a big reason. Families often feel they have little choice but to sign up.

"As soon as a best friend gets an unlimited-texting plan, you're paying for all those free messages," she said.

"All families need is one month of a surprise $1,000 bill, and they switch over to unlimited, too."

Without a per-text charge, the motivation for sending long, information-packed texts disappears, and the quick hits reign. One Worthington woman said her stepdaughter managed to send nearly 30,000 texts in just one month.

"I would call it an obsession," Amy Clark said. "The bill was, like, 60 or 70 pages."

Kyle Moore, a junior at Grandview Heights High School, said his mom wasn't interested in seeing him set text records. She requires him to use a prepaid phone.

"I learned really quickly that I was a textaholic," he said. "This keeps it under control."

The Pew report also said teens and families are wrestling more than ever with the most negative side effects of teen cell-phone use - distracted driving, "sexting," mobile harassment and unwanted text messages. "That's the downside," Lenhart said. "It's disruptive."

Still, most families wouldn't want their teens to be without cell phones. "It's a way for them to stay in touch and it enables them to manage the logistics of their lives in a way they can't imagine doing without," Lenhart said.

Dean said she wrote a paper on the subject for school. Her phone, she explained, contains the touchstones of her life.

"All my pictures, videos, music, internet, my contacts," she said. "When I broke it, I don't know how I survived."

Asked how she broke it, Dean giggled. "I thought my phone had superpowers or something," she said.

It rang, and she answered -- in the shower.