Theory of mind is defined as 'the ability to attribute mental states (such as beliefs, intentions, desires, goals etc) to self and others and to appreciate that behaviours are guided by these mental states.' Theory of mind is known to be deficient in people with schizophrenia and a study of 31 people in the U.S. used brain scans to compare what went on in people's brains when they were using theory of mind. Two groups - one with schizophrenia and a healthy control group were asked to attribute mental states to characters in a story of their own creation. Compared to the control group the people with schizophrenia had a lower flow of blood in parts of the left hemisphere of the brain including the frontal and visual association cortices, the posterior hippocampus and the insula. However, they had a higher blood flow in the right hemisphere - including the multiple frontal and parietal regions, the insula, the visual association cortex and the pulvinar - suggesting that they were using this part of the brain to compensate.
Andreasen, Nancy C., Calage, Chadi A. and O'Leary, Daniel S. - Theory of mind and schizophrenia: a positron emission tomography study of medication-free patients Schizophrenia Bulletin July 2008, 34(4), 708-719