Auditory hallucinations are one of the main symptoms of schizophrenia. Researchers have sought to understand the biological origins of these “voices”. They found that the ability to experience these hallucinations appeared long before the disease was diagnosed, sometimes even in childhood.
In schizophrenia, as in other illnesses, it is important to make a diagnosis as early as possible. Intervening at the right time delays the development of mental illness and the transition to psychosis, which can lead to suicide. 80% of people with schizophrenia have auditory hallucinations. They hear voices. These usually appear in adolescence or early adulthood, and can significantly affect their living conditions.
A scientific team from the Mount Sinai School of Medicine (New York, USA) tried to understand the biological origins of these auditory hallucinations. To do this, the researchers used a medical imaging technique to compare the auditory cortex of people with schizophrenia to that of people without the disease. They found that schizophrenic patients had an abnormality. The results of the study are published in the journal NPJ Schizophrenia.
An anomaly of the auditory cortex in question
“Since auditory hallucinations sound like real voices, we wanted to check whether patients with such experiences had abnormalities in the auditory cortex, which is the part of the brain that processes real sounds from the external environment,” explains Sophia Frangou, professor of psychiatry and lead author of the study. The researchers used a scanner to obtain high-resolution images of the participants’ brain activity as they listened to high and low frequency tones. Of the participants, 16 patients had schizophrenia and 22 were healthy. The science team found that most sound frequencies appeared “scrambled” on parts of the auditory cortex of schizophrenic participants.
It would be possible to identify vulnerable people very early
“The results of our study suggest that the vulnerability to developing ‘voices’ is related to a deviance in the organization of the auditory system that occurs during infancy and precedes the development of speech and the onset of psychotic symptoms of many years later. This is particularly exciting, because it means that it would be possible to identify potentially vulnerable people very early on, such as the children of patients with schizophrenia”, says Professor Sophia Frangou. In other words, analyzing the auditory cortex would make it possible to identify vulnerable people even before the appearance of symptoms. In the future, the scientific team will reproduce these observations on larger samples.
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