Cognitive function generally is divided into two areas: basic functions, which govern language, memory, visual perception and the like; and executive function, which enables the basic functions to work together to complete a goal.
"The executive functioning works like an executive behind a desk, giving direction to all the basic cognitive functions," said Julie Suhr, an assistant professor of psychology at Ohio University and author of the study. "In some people with schizophrenia, it appears that the executive is unable to work, leaving basic cognitive functions unsupervised. For some tasks, this may not matter. But for tasks that require you to adapt to new information, the lack of an executive may make a big difference."
For example: A factory worker builds products that move from left to right on a conveyor belt. New machinery reverses the belt's direction to right to left. A person with normal executive functioning may have some difficulty adjusting at first, but eventually will adapt. But for a person with an executive functioning problem, this change in routine is unsettling, and can leave the individual unable to complete the task at all.
"The alarm in their brain doesn't go off to tell them to turn off that overlearned behavior and make the adjustment," Suhr said. "They may be unable to function under these new circumstances."
In a new study of people potentially at high risk for schizophrenia or other psychotic disorders, Suhr found that executive functioning problems exist before the onset of psychosis, which could give mental health professionals a good indicator of future problems.
None of the 98 people who participated in the study had been diagnosed with schizophrenia. But 56 were identified as high risk through several tests designed to detect unusual thought patterns that are symptoms of "schizophrenic-like" behaviors. There was no difference in IQ between the high-risk and low-risk groups, and participants ranged in age from 18 to 22.
Study participants in the high-risk group scored worse on executive functioning measures than the low-risk group, a result that mirrors similar testing of people with diagnosed schizophrenia.
"Risk for schizophrenia is not yet clearly defined," Suhr said. While scientists know that people with a family history of schizophrenia are more likely to have the mental illness, there is no way to know which people within that high-risk group will develop schizophrenia. If executive functioning problems serve as an early warning sign, as Suhr's study suggests, mental health professionals can test for it.
"Eventually we may be able to develop preventive therapy to intervene before psychotic episodes disrupt the patient's life," she said. "Knowing that executive functioning problems exist early on also tells us more about the physiological nature of schizophrenia, which clearly is a brain disorder."
The next phase of the research will include a follow-up of the high-risk participants in her study and new work to explore other at-risk populations. The first study, which was funded in part by the scientific research society Sigma Xi, appeared in a recent issue of the journal Schizophrenia Research.
Contact: Julie Suhr, (614) 593-1091; firstname.lastname@example.org
Written by Kelli Whitlock, (614) 593-0383; email@example.com