American college students are hooked on mobile phones, social media and the internet and showing symptoms similar to drug addiction, according to a new study.

Researchers at the University of Maryland who asked 200 students to give up all media for a full day found that, after 24 hours, many showed signs of withdrawal, craving and anxiety along with an inability to function well.

Susan Moeller, the study's project director and a journalism professor at the university, said many students wrote about how they hated losing their media connections, which some equated to going without friends and family.

"I clearly am addicted and the dependency is sickening," said one student. "Between having a Blackberry, a laptop, a television and an iPod, people have become unable to shed their media skin."

Moeller said students complained most about their need to use text and instant messages, email and Facebook.

Few students reported watching TV news or reading a newspaper.

The American Psychiatric Association does not recognise internet addiction as a disorder.