Today, over 2 million people are suffering from Schizophrenia. The symptoms of Schizophrenia fall into three categories: positive symptoms, negative symptoms, and cognitive symptoms. Little is known about the neurobiology of this disease, particularly concerning circuits and molecules. Impairments within the various circuits and molecules affects cognition in the disease. A recent study published in the Journal of Neuroscience provided evidence that deficits in a brain chemical may be responsible for some of the debilitating cognitive effects such as poor attention, memory, and problem-solving skills. This is one of the first studies to explore the strong correlation between cognitive deficits and and a decrease in a particular neurotransmitter. Schizophrenia sufferers are subject to visual and auditory hallucinations as well as cognitive difficulties that interfere with everyday activities.
This study looked at the neurotransmitter, GABA, which has played a role in cognitive difficulties for people who have schizophrenia. Researchers GABA levels in the visual cortexes of 13 patients with the disorder and 13 patients without the disorder. Measurements were conducted with high-field magnetic resonance spectroscopy. Schizophrenic patients were found to have a deficit in GABA of about 10% to those without the disease. The second part of the study looked at the neurochemical deficit on cognitive behavior. GABA levels were assessed by showing patients a well-known illusion in which a presence of a high contrast surrounding region inhibits the ability to perceive information in the center of the visual field. Research showed that the surround-suppression illusion had a less effect on schizophrenia patients which was an unusual situation because they out performed healthy subjects. The researchers found that the lower levels of GABA in patients were responsible for the abnormal behavior.
This research provided support for targeting the GABA system for treatment of cognitive decline in schizophrenia.