Schizophrenia patients and their unaffected relatives have smaller volumes of prefrontal lobe gray matter, a new report suggests.
In schizophrenia patients, this finding was associated with worse working memory performance, compared with their unaffected relatives and healthy controls, noted Vina M. Goghari, Ph.D., of the University of Calgary’s Hotchkiss Brain Institute and her colleagues at the University of Minnesota and the Minneapolis Veterans Affairs Health Care System.
© Riley Brandt/University of Calgary
Dr. Vina M. Goghari
The investigators recruited about 30 schizophrenia patients and their nonpsychotic relatives from the Minneapolis VA Medical Center. They completed the Structured Clinical Interview for DSM Disorders (SCID) and the psychosis module of the Diagnostic Interview for Genetic Studies (DIGS) for each participant. They assessed Axis II cluster A traits using the Structured Interview for Schizotypy (SIS) in relatives and a control group of healthy volunteers. The patients’ current symptoms were assessed using the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS).
Finally, all participants’ psychiatric functioning was assessed using the Brief Psychiatric Rating Scale (BPRS).
After noting the participants’ medication use, Dr. Goghari and her colleagues found that schizophrenia patients tended to be on more antidepressants and other psychiatric medications, compared with controls. Relatives were more likely to be on more antidepressants, compared with controls (Schizophr. Res. 2014;153:113-21).
The researchers used structural MRI (a standard MP-RAGE sequence) to study the brains of 24 schizophrenia patients, 21 nonpsychotic relatives of schizophrenia patients, and 37 control subjects. A Freesurfer image analysis suite was used to better measure volumetric segmentation, cortical reconstruction, and cortical and subcortical parcels.
Researchers also gave participants (30 schizophrenia patients, 25 nonpsychotic relatives, and 30 controls) a spatial working memory task with maintenance and maintenance/manipulation sections. For the maintenance condition, "participants were asked to remember the location of three filled circles and, after a delay, respond whether a second set of three circles was a spatial match or not." In the manipulation condition, "participants were asked to mentally mirror flip/rotate an initial image consisting of three filled circles, and after a delay respond if a second set of circles was a mirror flip or not."
Analyses revealed that "both schizophrenic patients and their nonpsychotic relatives had less bilateral superior frontal gray matter, compared to controls." However, in the working memory test, schizophrenia patients performed less accurately than did their relatives and the controls, indicating that "nonpsychotic relatives may rely on compensatory brain mechanisms that preserve working memory performance."
In developing novel pharmacological and cognitive interventions, "family members may serve as a sample to investigate neural and behavioral compensatory mechanisms that lead to intact executive control," the authors said.
The study was funded by the University of Minnesota, the Natural Sciences and Engineering Research Council of Canada, the University of Calgary, the Canadian Institutes of Health, the U.S. Department of Veterans Affairs, and the U.S. National Institutes of Health. The authors reported no relevant financial conflicts of interest.