People with schizophrenia have different levels of the neurotransmitters glutamate and gamma-aminobutyric acidergic (GABA) than healthy people do, and their relatives also have lower glutamate levels, according to a study published online in Biological Psychiatry.
Using magnetic resonance spectroscopy, researchers discovered reduced levels of glutamate — which promotes the firing of brain cells — in both patients with schizophrenia and healthy relatives. Patients also showed reduced levels of GABA, which inhibits neural firing. Healthy relatives, however, did not.
Researchers are unsure why healthy relatives with altered glutamate do not show symptoms of schizophrenia or how they maintain normal GABA levels despite a predisposition to the illness.
“This finding is what’s most exciting about our study,” said lead investigator Katharine Thakkar, PhD, assistant professor of clinical psychology at Michigan State University, East Lansing. “It hints at what kinds of things have to go wrong for someone to express this vulnerability toward schizophrenia. The study gives us more specific clues into what kinds of systems we want to tackle when we’re developing new treatments for this very devastating illness.”
The study included 21 patients with chronic schizophrenia, 23 healthy relatives of other people with schizophrenia not involved in the study, and 24 healthy nonrelatives who served as controls.
Many experts believe there are multiple risk factors for schizophrenia, including dopamine and glutamate-GABA imbalance. Drugs that regulate dopamine do not work for all patients with schizophrenia. Dr. Thakkar believes magnetic resonance spectroscopy may help clinicians target effective treatments for specific patients.
“There are likely different causes of the different symptoms and possibly different mechanisms of the illness across individuals,” said Dr. Thakkar.
“In the future, as this imaging technique becomes more refined, it could conceivably be used to guide individual treatment recommendations. That is, this technique might indicate that one individual would benefit more from treatment A and another individual would benefit more from treatment B, when these different treatments have different mechanisms of action.”
Thakkar KN, Rösler L, Wijnen JP, et al. 7T proton magnetic resonance spectroscopy of GABA, glutamate, and glutamine reveals altered concentrations in schizophrenia patients and healthy siblings [publisehd online ahead of print April 19, 2016]. Biological Psychiatry.
Study uncovers clue to deciphering schizophrenia [press release]. Washington, DC: EurekAlert!; June 7, 2016.