Auditory hallucinations, often experienced by patients with certain mental disorders such as schizophrenia, are likely caused by abnormalities in two brain processes. A new study published in PLOS Biology found that individuals with auditory hallucinations have issues with a “broken” corollary discharge that fails to suppress self-generated sounds, as well as a “noisy” efference copy that intensifies the brain’s perception of these internal sounds. This can lead to patients hearing voices in the absence of any external stimuli and difficulty distinguishing between their own thoughts and external voices.
The researchers conducted EEG experiments on twenty patients diagnosed with schizophrenia who experienced auditory hallucinations and twenty patients diagnosed with schizophrenia who did not have such hallucinations. They found that when patients with auditory hallucinations were preparing to speak, their brains did not suppress internal sounds as they should have and actually had an enhanced response to internal sounds other than the planned syllable. These findings suggest that impairments in the corollary discharge and efference copy processes contribute to auditory hallucinations and could potentially be targeted for new treatments in the future.
Patients who suffer from auditory hallucinations can hear sounds without any external stimuli, which can lead to confusion between reality and fantasy. The study suggests that there are functional connections between the motor and auditory systems in the brain that are impaired in individuals experiencing auditory hallucinations, leading to difficulties in distinguishing between internally generated sounds and external stimuli. This loss of ability to differentiate between reality and fantasy may contribute to the development of auditory hallucinations in patients with certain mental disorders.
The study sheds light on the neurological mechanisms behind auditory hallucinations and provides insight into potential targets for future treatments. By understanding the processes involved in auditory hallucinations, researchers may be able to develop new interventions to help patients better distinguish between self-generated sounds and external stimuli. This could lead to improved management of symptoms and a better quality of life for individuals experiencing auditory hallucinations.
Overall, the study highlights the importance of understanding the brain processes involved in auditory hallucinations and how they contribute to symptoms in patients with mental disorders such as schizophrenia. By identifying abnormalities in the corollary discharge and efference copy processes, researchers may be able to develop more targeted treatments for individuals experiencing auditory hallucinations. This research opens up new possibilities for improving the lives of patients with mental disorders and addressing the complex nature of auditory hallucinations in clinical settings.