Excessive internet use may cause parts of teenagers' brains to waste away, a study reveals. Scientists discovered signs of atrophy of grey matter in the brains of heavy internet users that grew worse over time. This could affect their concentration and memory, as well as their ability to make decisions and set goals. It could also reduce their inhibitions and lead to 'inappropriate' behavior. Experts said that their results suggested long-term internet addiction would result in brain structural alterations. The study was carried out by neuroscientists and radiologists at universities and hospitals in China, where 24 million youths are estimated to be addicted to the internet. In Britain, children spend an average of five hours and twenty minutes a day in front of TV or computer screens, according to estimates by the market-research agency Childwise.