This virtual reality experience may seem like a bit of fun, but it's also helping researcher Dr Charlotte Gayer-Anderson assess adolescents for early signs of mental health conditions.

The students are being led through a VR school canteen in which other children behave neutrally, but the way in which the students interpret the behavior is a predictor for conditions such as anxiety and depression.

The pupil asks: "Did she say Hi to me? I think so.”

As they are led through the specially created world that mimics a school social environment, the students respond to the avatars.

One pupil decides he's not keen on an avatar that refuses to allow him to sit beside him. "Oh what? He said I can't sit there. I don't like him."

But he warms towards another avatar and says: "Hello."

Dr Charlotte Gayer-Anderson is responsible for researching the virtual reality component of REACH – a study looking at how to treat mental health in adolescents.

"We are asking young people in schools in south London to go into in a canteen environment and what we've tried to create are ambiguous social situations. And we ask the adolescents to interact with the computer characters and we're interested in how they perceive those interactions. So, for example, there's one interaction where a boy is sitting at a table with a bag, and as the student, the adolescent, approaches the boy puts the bag on a seat and says: "You can't sit here, I'm waiting for someone.”

"And what we found and what we're really interested in is how adolescents perceive those interactions completely differently. So some young people will perceive that interaction as really quite threatening and anxiety provoking and feel that they're disliked by the boy sitting at the table, whilst other young people will perceive it that the boy is having a really bad day and just wants to be left alone," she says.

"We know that 75 percent of all adult mental health problems begin before the age of 17 or 18. So if we can intervene early, if we pick up on low threshold symptoms of anxiety and try and intervene and try to prevent that from progressing into a more serious anxiety disorder, then that's where I feel we'll be able to make most of the difference," adds Dr Charlotte Gayer-Anderson.

Professor Craig Morgan, head of the adolescent mental health project REACH, believes virtual reality could transform the way young people are treated.

"When we began to use tablet computers the kids loved it and were much more engaged, and then when we introduced viral reality, we literally now have kids queuing up to have a go, because it's something they relate to in their daily lives and that they enjoy and that seems like fun. So it doesn't feel to them like a traditional assessment of mental health problems.”

Dr Charlotte Gayer-Anderson encourages the teenagers to interact with the avatars.

She guides them through the virtual reality world, making sure the technology is clear and they can control their avatar.

The virtual reality being tested at King's College London includes a simulation set on a bus and another in a pub, two common trigger points for people with anxiety.

Head of the Virtual Reality Lab Dr Lucia Valmaggia says the VR makes the job of the therapist more practical and increases the scope of what they can achieve.

"Initial evidence shows that, the same therapy can be done in fewer seasons because it's so much more effective in exposing people to the things that they're afraid of. So it could save time and therefore make more therapists available in that sense, the therapy could become shorter. However it's still not at the stage where people can take it home and do it on their own. So it's very much something that you need to do with therapist. One of the things we're researching is by making it into a protocol so by writing exactly each step that needs to be done, maybe it could assist therapists with less experience in doing some of the things that otherwise you would need more experience to do," says Dr Lucia Valmaggia.

Research into how virtual reality can be used to assess and treat patients with mental health conditions is still in the very early stages.

Scientists at King's College say VR therapy works by enabling patients to practice how they would respond in a real situation, it is not yet known whether it can create new neural pathways in the brain.

It has proven useful as a tool for identifying potential mental health conditions in teenagers, when problems are still manageable.

Most patients wait at least ten years before seeking help, by which point their problems are harder to resolve.

The VR is also particularly useful for teenagers as they find the approach unthreatening and enjoyable.