A new study of computer gamers has found that a session in front of World of Warcraft can make players less stressed and more calm.

The study questioned 292 male and female online gamers aged between 12 and 83 about anger and stress. They then played the game for two hours and were retested.

"There were actually higher levels of relaxation before and after playing the game as opposed to experiencing anger, but this very much depended on personality type," said team leader Jane Barnett from Middlesex University.

"This will help us develop an emotion and gaming questionnaire to distinguish the type of gamer who is likely to transfer their online aggression into everyday life."

Barnett's paper was presented at the British Psychological Society's annual conference in Dublin.

The conference also heard that people who play computer games obsessively display similar characteristics to those suffering from Asperger syndrome.

Dr John Charlton, of the University of Bolton, and Ian Danforth, of Whitman College in the US, found that the personalities of gamers became more akin to Asperger sufferers the deeper their addiction becomes.

This is typically characterised by neuroticism, and lack of extraversion and agreeableness.

"The thinking in the field is that there is a scale along which people, even those considered to be 'normal', can be placed on," said Dr Charlton.

"And that people such as engineers, mathematicians and computer scientists are nearer to the non-empathising, systemising end of the spectrum, with people with Asperger syndrome even further along again.

"Our research supports the idea that people who are heavily involved in game playing may be nearer to autistic spectrum disorders than people who have no interest in gaming."