Schizophrenia Daily News Blog

Researcher Simulates Symptoms of Schizophrenia In People Without The Disorder

University of Missouri-Columbia researchers haven attempted to simulate a symptom of schizophrenia in people who don't have the illness, in hopes of better understanding the disorder and its impact. They simulated - the inability to speak clearly or respond to questions in a precise manner - which is considered a common cognitive deficit in those with schizophrenia.

"This study is about working with people who are not schizophrenic and observing whether, under experimental conditions, we could make them act like people with schizophrenia," said John Kerns, assistant professor of clinical psychology in the College of Arts and Science. "In the lab, we challenged their working memory ability as they spoke and simulated deficits found within people with schizophrenia."

He found that by putting rigorous demands on the working memory – which is the temporary storing of information that we hold readily available to use, like memorizing someone’s phone number when we don’t have a piece of paper and need to call them right back – communication disturbances, or poor communication skills occurred.

The study also revealed that an even greater degree of speech disorganization happens when other mental processing requirements are combined with working memory stress.

There were 82 healthy participants in the study. While conducting speech tasks, Kerns manipulated the levels of stress on their brains. Participants were asked to talk while listening to letters through a set of headphones. In another phase of the study, they looked at a picture on two separate occasions and were asked to tell two completely different stories about the picture. The sessions were recorded and Kerns' research team evaluated the data and scored the speech impairments.

"Potentially, performing any secondary task, while speaking, will throw off your speech because of a general increase in cognitive demands," Kerns said. "We wanted to compare conditions and see if doing any task disrupts speech, or is it specifically working memory demands. We found that it was only the working memory demands that caused an increase in disorganized speech."

Findings from this study are consistent with a recent experiment related to the illness. In May, Kerns established a link between poor communication skills and working memory in people with schizophrenia. However, no causation was established because the study was correlational (meaning there is a relationship between these factors, but no cause and effect was found, because of the structure of the study) and working memory ability or level of symptoms could not be experimentally manipulated.

"It's two ways of reaching the same conclusion," he said. "In the study with patients, we find that working memory correlates with disorganized speech. With healthy people, working memory manipulation causes an increase in disorganized speech."

The current study "Experimental Manipulation of Cognitive Control Processes Causes an Increase in Communication Disturbances in Healthy Volunteers" [article abstract] appears in the July 2007 issue of Psychological Medicine.

Kerns' previous study "Verbal Communication Impairments and Cognitive Control Components in People with Schizophrenia" was published in the May 2007 issue of the Journal of Abnormal Psychology.

Source: University of Missouri-Columbia