What started as one man's quest for a lava lamp has developed into an online auction habit that he incorporates into his daily to-do list.

Chris, 38, spotted a unique lamp on a television show a few years ago and wanted one. His search began on the show's chatboard where he posted a request for information on the lamp. Someone who conducted her own futile search for the same lamp replied to the posting and suggested that he check online auction sites, especially eBay.

A seller eventually placed the elusive lamp on eBay and, after submitting several bids, Chris won. And developed a penchant for online auction sites.

"It's kind of silly to say I'm hooked on the site, but I check eBay at least twice a day," said Chris, who requested a pseudonym. "If I don't check it in the morning I say, 'Oh, I need to check eBay longer at night now because I didn't do it this morning'."

While online auction sites connect buyers to items they may not find in their local stores or that help them complete collections, some users become addicted to such sites. Online auction site addiction is an example of the greater trend of internet usage disorder.

With the internet's advent "you just get into some issues that weren't there before," said Dr Kimberly Young, who founded The Center for Online Addiction. "People are scrambling to get a better understanding of this [internet addiction]."

Young notes that online auction sites have an element of winning that differentiates them from standard shopping sites. This component as well as clinical symptoms, such as self-esteem problems, may lead to internet addiction disorder, she said.

Dr Maressa Hecht Orzack, director of the Computer Addiction Studies Center at McLean Hospital in Belmont, Massachusetts, and an assistant professor at Harvard Medical School, also discovered these traits in the patients she treats for online auction site disorder.

"There is always something else going on. Some have social phobia or anxiety or don't feel comfortable in real life. That is like any addictive behaviour," Orzack said. "They may win a bid and they get excited."

Orzack conducts clinical interviews with her patients to determine what major issues are going on in their lives.

"If something big is going on in their life they're going to escape," she said. "We talk about other methods of dealing with stress. We reinterpret what is going on in their lives."

Some internet addicts are lonely and turn to the web because there is "a sense of community on the net, a sense of belonging. They're looking for excitement", she said.

Internet use moves from the level of casual surfing to complete addiction when the action dominates and controls a person's life, according to The Center for Online Addiction's website. The effect of a person's time on the internet, not the amount of time spent online, also determines if a person has a net addiction, according to Young's website. No single factor defines internet addiction.

"When there are clinically diagnosed symptoms of addiction that's where you differ from a hobby," Young said.

Left unchecked, excessive virtual bidding can negatively affect reality. Overspending at online auctions holds financial consequences. Some internet users lie to their spouses to conceal how much they spend on auction sites.

The internet's pervasiveness means that eliminating web use isn't a viable treatment option. Rather, cures centre on self control and controlled internet use.

"Basically it is like a food disorder. You can't stop eating. You can't remove the internet. You need to have controlled use, identify what the problems are and modify the behaviour," Young said.

"The issue with the 'net is people need it for work and school," Orzack said. "They get into a mind set of 'Oh, I'm going to just go and check it out,' but they can't. They need to learn self control. They need to ask, 'When is this important?' I ask them what is the worst that can happen if they don't go on the internet?"

Young and Orzack say that the criticism they received when they began discussing internet addiction has subsided. The number of patients Orzack treats for the disorder has increased and Young now advises corporations on the issue.

"People who say it isn't like substance abuse, well, their moods change," Orzack said. "That means their brains must be affected. And it needs to be addressed. And it doesn't go away."

Despite possessing some of the symptoms associated with 'net disorder, Chris said auction sites don't interfere with his life. However, he sees how addiction can develop.

"You think you need just one more thing and then you see something else and you think that would look good and that is all I need," Chris said. "There is always something else."