Thousands of Sega's Dreamcast machines had been pre-purchased, and punters eager to pit their wits against cyber space opponents were willing to queue through the night to get their hands on one.

By now, some of those machines may have been plugged in for hours, and their users deeply immersed in gaming for a lot of that time.

Psychologists have been warning of the possible health effects of logging out of real life and into virtual gaming for some time.

Some fear that prolonged and excessive roaming around the abandoned stations of Resident Evil, or guiding little Sonic around his hedgehog maze, can actually damage a young person's ability to develop social skills.

Queues for the launch of Dreamcast

And they predict that increasing purchases of games machines may eventually result in a whole raft of socially inept young adults.

And because Dreamcast offers, for the first time, access to the internet through a gaming machine, it has also sparked concerns about internet addiction.

Places like the Center for On-Line Addiction in the USA warn that extreme violence in children, such as Columbine High School shootings, may be caused or propagated by hours spent online.

'No police'

Dr Kimberly S Young, assistant professor of psychology at the University of Pittsburgh at Bradford, and author of Caught in the Net: How to Recognise the Signs of Internet Addiction and a Winning Strategy for Recovery, offers a warning on the centre's website.

She writes: "The internet is a big city with no police.

"The Colorado shootings demonstrated the kinds of activities many kids are engaging in while completely unsupervised online."

Excessive use of video games and the internet can result in withdrawal, tiredness and hampered development of social skills, she adds.

Children need time to play and socialise

She writes: "So many kids have come to me and admitted they have developed problems from their abusive use of the internet.

"When I ask them if they have shared their concerns with their parents, they say, 'No way! My parents are clueless about what goes on over the net and why I can't stop using it. If they found out the truth they'd freak.'

"Parents tell me they ignore the dozens of hours per week kids spend online because they assume it's purely educational, or at least better than TV."

Head of psychology at Nottingham Trent University, Dr Mark Griffiths, said that funding into long-term research into the effects of exposure to multimedia were greatly needed.

Maintain a balance

But he warned against hysteria, saying that access to computer and games facilities are beneficial to children, so long as it is supervised and in moderation.

He said: "Basically, kids have to get a mixture of different things in the right proportions to maintain a balance. They need education - the traditional three Rs - social contact with their friends, peers and family, and physical education and sport.

"If any one of those things is gained in excess, to the detriment of the others, you are not going to end up with a well-rounded individual.

"And age is very important. If up until the age of 18, a person has had a good balance of these things, but then decides to devote several hours of each week to playing video games, then they are not going to damage their developmental skills, because they have already developed them.

Girls don't get social approval for playing video games

"They may incur immediate problems and those around them may detect behavioural changes, but there's generally no lasting damage."

However, he said that for a child under 10 to be removed from social contact for the same amounts of time was potentially damaging to its social learning. Supervision, he said, was the key.

But it's not just the case that uncaring parents are happy to leave their offspring in the care of a cyber surrogate for hours at a time.

Often parents are just keen for their children to develop an interest in a medium which they see as crucial for their academic and job prospects.

"There's definitely a technology gap between parents and their children, and parents can be technophobic and decide that where the computer is concerned, their children might know best.

Multimedia units

"That's why computer classes in schools from as early an age as possible are terribly important," he said.

He said that there was a well-documented tendency in recent years for families to "cocoon", ordering food to be delivered to the door, seeking entertainment on a screen, and taking very little exercise.

"Obviously, that is something that has to be looked at, because children - and their parents for that matter - need to be able to run around and get exercise.

"In the next 20-30 years, we are all going to be carrying multimedia units where we will be able to work from, play games from, communicate with other people on, and we've got to get used to the way we need to accommodate this technology into our lives.

"Computers and video machines are great in the right circumstances - and the vast majority of people use them in a beneficial manner. You've just got to be sensible about it."