Blood Flows Differently Through Schizophrenic Brains
Schizophrenia is a complex chronic brain disorder whose cause remains relatively unknown. Recent research has suggested that some patients with schizophrenia may have a higher rate of rare genetic mutations that possibly disrupt brain development. A new study from the University of Bonn in Germany may have discovered a physical defect in the brains of schizophrenic patients which cause a difference in cerebral blood flow.
In the study group of 36 volunteers, 11 of whom had non-medicated schizophrenia, the researchers used a magnetic resonance imaging (MRI) technique called continuous arterial spin labeling or CASL which maps out cerebral blood flow patterns using arterial blood water that is magnetically labeled instead of radiation or contrast agents.
Compared to the healthy controls, the schizophrenic patients had extensive areas of hypoperfusion, or a reduced flow of blood, through the frontal lobes, frontal cortex, anterior and medial cingulated gyri, and the parietal lobes. These regions are associated with cognitive functions such as planning, decision-making, judgment, and impulse control.
By contrast, the patients had hyperperfusion, or increased blood flow, in the cerebellum, brainstem, and thalamus.
Schizophrenia is a mental disorder that makes it difficult to tell the difference between real and unreal experiences, to think logically, and to behave normally in social situations. Symptoms vary per individual and can include hallucinations, delusions, disordered thinking, movement disorders, social withdrawal, and cognitive deficits.
The current therapy for schizophrenia is antipsychotic or neuroleptic medications which change the balance of chemicals in the brain – primarily dopamine and glutamate - helping to control symptoms. The medications are effective, but can have unwanted side effects such as sleepiness, feelings of restlessness, and problems with movement and gait. Antipsychotic medications may also lead to weight gain and metabolic changes that increase the risk of diabetes and hyperlipidemia.
Most cases of schizophrenia are diagnosed based on a thorough interview of the patient and his or her family members. There are no laboratory diagnostic tests currently available, however CT scans of the head and other imaging techniques may find some neurological abnormalities that occur with schizophrenia, such as an enlargement of the lateral ventricles, decreased brain tissue and volume, or lowered brain activity in certain regions.
"Our CASL study revealed patterns of hypo- and hyperperfusion similar to the perfusion patterns observed in positron emission tomography (PET) and single photon emission computed tomography (SPECT) studies of schizophrenic patients," said study author Lukas Scheef MD. "CASL MRI may allow researchers to gain a better understanding of schizophrenia. In the long run, it may help to individualize and optimize treatment."
Schizophrenia affects about 1.1 percent of the US adult population, according to data from the National Institutes of Mental Health. It occurs equally as often in men and women, although men are usually affected earlier in life. Symptoms typically develop in men in late teens or early twenties, while women most often show signs in their twenties and thirties.
The findings of the CASL study appear in the July issue of the journal Radiology.