New York: Nearly 75 percent of the college students in the US are dependent on smartphones while one in five consider themselves to be "lost" without the device, says a study.

While 86 percent said they sleep with their phone within an arm's reach, 81 percent replied that they would panic if they lost their phone.

"Smartphones have helped nurture a culture of impatience in which one in four people abandon a web page that takes more than four seconds to load," wrote researchers from the Alabama State University in Montgomery, Alabama.

"That spills over into a modern world where instant access has become the norm and deep-thinking is getting short shrift," they added.

The study found that 63 percent college students think they hear their phone when it makes no sound while 55 percent use their phone to escape from problems or to get relief from a bad mood.

Some of the reasons to be dependent on smartphones are practical.

"For instance, women felt safer when they had their phones with them and said they were more likely to panic if they couldn't find it," researchers said.

According to them, in an age of constant online interaction, people rarely take time to deal with their own thoughts and have become increasingly lonely, feeding a sense of self-alienation.

The study titled "The Truth About Smartphone Addiction" is set to appear in the national College Student Journal.