The preliminary results of an investigation by the Danish part of the World Health Organisation into the well-being of children found that 4,000 of those interviewed had severe welfare problems. Another recent investigation into the health of more than 3,000 sixth-formers at the six gymnasier (sixth-form colleges) in Roskilde, south and west of Copenhagen, discovered that almost half suffer regularly from stomach ache, headache, sleeping difficulties and muscular tension. A third say they feel stressed, and many blame the school system. Most of the sufferers use pain-killers, tranquillisers and sleeping pills. An increasing number suffer from anorexia and bulimia, and many attempt suicide.