Washington: Children normally experience flights of fancy, including imaginary friends and conversations with stuffed animals, but some of them also have hallucinations and delusions which might be the early signs of psychosis.
A study of British 12-year-olds that asked whether they had ever seen things or heard voices that weren`t really there, and then asked careful follow-up questions, has found that nearly six percent may be showing at least one definite symptom of psychosis.
The children who exhibited these symptoms had many of the same risk factors that are known to correlate with adult schizophrenia, including genetic, social, neurodevelopmental, home-rearing and behavioural risks.
"We don`t want to be unduly alarmist, but this is also not something to dismiss," said co-author Terrie Moffitt, professor of psychology, neuroscience, psychiatry and behavioural sciences at Duke University.
The children were participants in the long-term Environmental Risk Longitudinal Twin Study in Britain, which includes 2,232 children who have been tracked since age 5 and reassessed at 7, 10 and 12.
At age 11, the children were asked about psychotic symptoms, but the researchers waited 15 years to see how, as adults, their symptoms matched what they reported at 11. By age 26, half of the people who self-reported symptoms at age 11 were found to be psychotic as adults.
"It looks like a non-trivial minority of children report these symptoms," said co-author Avshalom Caspi, Moffitt`s counterpart at Duke.
The findings provide more clues to the development of schizophrenia, but don`t solve any questions by themselves, said co-author Richard Keefe, director of the schizophrenia research group in the Department of Psychiatry and Behavioral Sciences at Duke, said a press release.
Schizophrenia often goes undetected until adolescence, when the first symptoms - anti-social behaviour, self-harm, delusions - begin to manifest in an obvious way.
But nobody knows whether the disease is triggered by the process of adolescence itself, or brain development or hormone changes. "It`s my impression that all of those things interact," Keefe said.
The study appears in the April issue of Archives of General Psychiatry.