TORONTO, Jan. 11 (UPI) -- People with schizophrenia showed greater brain activity during tests that induce a brief, mild form of delusional thinking, researchers in Canada say.
Dr. Mahesh Menon of the Center for Addiction and Mental Health said this type of delusion occurs in as many as two-thirds of people with schizophrenia.
"We studied a type of delusion called a delusion of reference, which occurs when people feel that external stimuli such as newspaper articles or strangers' overheard conversations are about them," Menon said in a statement. "Then they come up with an explanation for this feeling to make sense of it or give it meaning."
The study involved 14 people with a schizophrenia diagnosis and 15 people in a control group.
Participants were presented with 60 statements while in an MRI scanner. For each statement, they were asked whether they felt it was about them.
Twenty statements were specific to each participant, and included details taken from initial screening interviews, but the remaining 40 statements were generic, and evenly divided between statements that were neutral or that had an emotional connotation.
The study, published in the journal Biological Psychiatry, found people with schizophrenia were just as likely as those in the comparison group to agree that personalized statements were about themselves -- but those with schizophrenia were significantly more likely to say that the generic statements referred to them.