The United States could be rife with Internet addicts as clinically ill as alcoholics, an unprecedented study released suggested.

Researchers at Stanford University School of Medicine in Silicon Valley said their telephone survey indicated more than one of every eight US residents showed at least one sign of "problematic Internet use."

The findings backed those of previous, less rigorous studies, according to Stanford.

Most disturbing was the discovery that some people hid their Internet surfing, or went online to cure foul moods in ways that mirrored alcoholics using booze, according to the study's lead author, Elias Aboujaoude.

"In a sense, they're using the Internet to self-medicate," Aboujaoude said. "And obviously something is wrong when people go out of their way to hide their Internet activity."

According to preliminary research, the typical Internet addict was a single, college-educated, white male in his 30s, who spends approximately 30 hours a week on non-essential computer use.