Schizophrenia sufferers are not fooled by a visual illusion and can judge it better than non-schizophrenic observers, according to new research.
The study by University College London (UCL) and King's College London, currently published in the Current Biology journal, says this may explain why some sufferers feel persecuted and mis-attribute people's actions.
In the tests, scientists used an illusion where an object's contrast appears to be reduced by its surroundings. Participants had to gauge the appearance of a medium contrast disk against a high contrast background.
Out of the 15 participants with chronic schizophrenia, 12 made more accurate judgements that the most accurate non-schizophrenic person in a control group of 30 people.
Dr Steven Dakin, of the UCL Institute of Ophthalmology, said: "We often think of people with schizophrenia as not seeing the world the way it really is - for example, driving hallucinations - but we have shown that sometimes their vision can be more accurate than non-sufferers."