A study recently published in NPJ Schizophrenia, led by researchers at the Icahn School of Medicine at Mount Sinai in New York City, suggests that people with schizophrenia develop the vulnerability to hear “voices” years before the onset of symptoms. Below, researcher Sophia Frangou, MD, PhD, FRCPsych, Professor of Psychiatry at the Icahn School, discusses the findings and further studies which are planned.
Q: What prompted your research on the biological origins of hearing “voices” in patients with schizophrenia?
A: As a practicing psychiatrist, I have witnessed how disturbing and frightening auditory hallucinations, commonly known as “voices,” can be and how difficult they are to treat; often they persist even when patients are getting the best treatment we can offer. I really want to understand which part or parts of the brain are responsible for “voices” so that we can try to find new ways to treat them.
Q: Please briefly describe your study and its findings.
A: Patients describe the “voices” are being “real”—meaning that they experience the “voices” as if they originate from the external world. We took these descriptions at face value and designed a study to test the integrity of the auditory cortex (ie, the part of the brain that handles external sounds) in patients with schizophrenia that had experienced “voices.” We also included healthy individuals as a comparison group. Everyone was scanned using a scanner with a 7 Tesla magnet to obtain high resolution images. During the scan, all participants listened to simple tones with low and high pitch.
We used this paradigm because it can reveal a fundamental property of the auditory cortex called tonotopy, which means that tones with different pitch activate different sections of the auditory cortex in an organised fashion. We found that the tonotopy of the auditory cortex was disputed in the patients with schizophrenia, linking the vulnerability to hearing “voices” with abnormality in the way the auditory cortex processes even basic sounds.
Q: Were any of the outcomes particularly surprising to the study team?
A: The study has two unexpected findings. First, it shows that vulnerability to “voices” is associated with abnormal sensory processing which does not involve any higher-order cognition. For decades, “voices” had been considered as abnormalities of thought rather than perception. Second, tonotopy is established very early in development, during fetal life and infancy, linking propensity to hearing “voices” to abnormal neurodevelopment of the auditory cortex.
Q: What are the possible real-world applications of these findings?
A: In my experience, patients are very interested in seeing images of brain regions that are implicated in hearing “voices” and they find comfort in knowing that these experiences are indeed symptoms of a problem inside the brain. Material from this study can therefore be used to discuss “voices” with patients and their families.
Q: Do you and your co-investigators intend to expand upon this research? What further studies do you feel are needed?
A: We plan to pursue research in 2 directions. First, we want to know if abnormalities in the auditory cortex are a general feature in people hearing “voices” or whether this type of brain abnormality is specific to schizophrenia. Second, we are testing the efficacy of noninvasive neuromodulation targeting the auditory cortex in treating “voices” in patients with schizophrenia.
Q: Is there anything else pertaining to your research and findings that you would like to add?
A: We hope that clinicians treating patients with schizophrenia will find these findings helpful in their work.
Sophia Frangou, MD, PhD, FRCPsych serves as Research Chair in Brain Health at the University of British Columbia, Canada and Professor of Psychiatry at the Icahn School of Medicine at Mount Sinai in New York City. Her work has greatly advanced the understanding of the pathophysiology of mood and psychotic disorders and made groundbreaking contributions to the characterization of brain mechanisms of “resilience”. She has authored more than 240 highly cited papers and has written or contributed to 10 books on mental illness. Dr. Frangou is a fellow of the European Psychiatric Association, the Royal College of Psychiatrists and the American Psychiatric Association.