GUT and chest infections in early childhood appear to raise the risk of developing schizophrenia later in life even if they do not spread to the brain, Australian scientists have discovered in a world-first finding that radically expands links between the psychiatric disorder and physical illness.

Boys who were admitted to hospital at least twice before age three with respiratory or intestinal infections were 80 per cent more likely than others to develop the disabling mental disorder by the time they were in their mid to late 20s, according to the study of the birth and hospital records of more than 40,000 young adults in Western Australia.

Previous research has shown an association between brain infections such as meningitis and schizophrenia, but the Curtin University study is the first to demonstrate a link with illnesses that rarely involve the central nervous system - suggesting widespread inflammation and the body's response to it may be sufficient to disrupt brain development.