By Kate Kelland LONDON (Reuters) - Computer programs can be taught to select between brain scans of healthy young people and scans showing adolescents who are at higher risk of developing mental disorders such as anxiety and depression, scientists said Thursday. In a study in the Public Library of Science (PLoS) ONE journal, British researchers said their findings suggest it may be possible to design programs to predict which at-risk adolescents will go on to have psychiatric problems, giving doctors more time to intervene before illnesses set in.