The findings are published in the scientific journal Translational Psychiatry.
Schizophrenia is a severely debilitating mental disorder characterized by hallucinations, delusions and cognitive decline. The condition has been linked to a variety of biological, social, and environmental factors as well as to changes in brain structure.
For example, the hippocampus in the temporal lobe is usually smaller in people with schizophrenia compared to those without the disorder. Researchers have been unsure whether these changes to the brain structure are a result of the disorder and/or its prescribed medications, or whether these changes were already present before the onset of symptoms.
For the study, a research team at the University of Basel examined the brain structures of individuals who were at risk of developing psychosis as well as those of patients who were experiencing the onset of psychotic symptoms for the first time.
Initially, scientists from the Adult Psychiatric Clinic of the University Psychiatric Clinics (UPK) and the Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN) observed no notable differences between the hippocampi of individuals at high risk and those of patients.
Next, in collaboration with scientists from the Transfaculty Research Platform, the Basel researchers investigated whether any known schizophrenia risk genes were associated with the hippocampus structure.
They did, in fact, find a connection.
The researchers found that the greater the number of risk genes a person possessed, the smaller the volume of their hippocampus. This was true regardless of whether they were a high-risk study participant or a patient.
This discovery suggests that a group of risk genes is connected with a reduction in the size of a critical region of the brain before the disorder manifests itself.
The findings offer a greater understanding of neurobiological factors contributing to schizophrenia. It is well-known that none of the wider risk factors (e.g. genes, environment, unfavorable social situation) can be used to predict the onset of psychosis in any specific person. However, the discovery may be of use for the treatment of schizophrenia.
“It is quite possible that individuals with smaller hippocampi will react differently to therapy compared to those with normally developed hippocampi,” said lead researcher Dr. Stefan Borgwardt of the Neuropsychiatry and Brain Imaging Unit.
The scientists are planning more studies to further confirm the therapeutic potential of this new finding.
Source: Universität Basel