TORONTO, April 29, 2008 -- A study released today by York University researchers has found that schizophrenia patients with superior verbal abilities are like similarly-gifted healthy people in many ways, but still have trouble functioning in the community.
The study is the first to confirm the existence of small numbers of schizophrenia patients with superior levels of verbal ability, defined as a vocabulary score in the upper five-to-ten percent of the general population.
Researchers investigated the cognitive performance, life skills and community independence of verbally gifted schizophrenia patients, comparing their abilities in these areas to those of verbally gifted healthy people. They found no significant differences between the two groups except in the ability to function independently in the community.
“Impaired cognitive performance is widely regarded as a core feature of schizophrenia and a major cause of disability in daily life,” says lead study author, Dr. Walter Heinrichs, a psychology professor in York’s Faculty of Health. “We’re seeing that this is not necessarily the case with these exceptional patients. They resemble similarly-gifted healthy people in most aspects of cognition as well as in daily living skills, but they still can’t function normally in the community.”
Researchers tested 151 patients, ranging in age from 21-65, alongside healthy people with no history of medical or mental illness. Twenty-five of these patients scored in the superior range. Heinrichs notes that the large number of patients tested meant it was possible to compare the gifted group with more typical schizophrenia patients, and with verbally gifted and average healthy people.
The gifted and more typical patient groups differed on virtually every comparison except the severity of their psychotic symptoms. The gifted group was significantly more independent than typical patients, but experienced equivalent levels of symptoms like delusions, hallucinations, apathy, and lack of motivation.
It was also noted that neither verbally-superior patients nor verbally-superior healthy subjects performed at superior levels on all cognitive tasks. Instead, oral reading, visual abstract reasoning, working memory, word fluency, learning and attention scores for both groups ranged between average and high-average levels.
“The discovery of verbally gifted patients is important because they offer a window on the schizophrenic brain when it is relatively free of the abnormalities underlying cognitive impairment,” Heinrichs says. “These patients also demonstrate that cognitive ability cannot be the only determinant of community adjustment in this severe form of mental illness.”
Heinrichs worked alongside York graduate students Ashley Miles and Narmeen Ammari, and psychologists Stephanie McDermid Vaz and Joel Goldberg.
The study, “Cognitive, Clinical, and Functional Characteristics of Verbally Superior Schizophrenia Patients,” is published in the journal Neuropsychology.
Media contact:
Melissa Hughes, Media Relations, York University: 416 736 2100 x22097 / mehughes@yorku.ca
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