Two new studies suggest the cause of visual and auditory hallucinations experienced in schizophrenia.
The first study is from the Montreal Neurological Institute and Hospital -The Neuro - at McGill University and McGill University Health Centre. It revealed that certain errors in visual perception in individuals with schizophrenia are consistent with interference or 'noise' in a brain signal known as a corollary discharge.
Corollary discharges enable different areas of the brain to communicate with each other. This enables us to be aware that we are thinking our own thoughts. An impaired corollary discharge might result in having a person think someone else placed the thought in his mind.
Recent research suggests an impaired corollary discharge can account for symptoms such as auditory hallucinations and delusions and disorganized thinking and speech.
The nature of the impairment was unknown. The study showed that the pattern of the mistakes the patients made correlated with the extent of their symptoms.
Researchers are hopeful to they can work backward from the behavioral data to the biological basis of the corollary discharge effects.
(Noisy brain signals: how the schizophrenic brain misinterprets the world, retrieved on April 30, 2014 from http://medicalxpress.com/news/...)
In other news:
Auditory hallucination in schizophrenia are tied to decreased brain current. This reduced activity occurs in the frontal and temporal brain regions. Hallucinating patients showed lower-amplitude responses in the frontocentral regions.
The electroencephalographic study examined patients with schizophrenia who were hallucinating, those who were not, and healthy controls. Hallucination severity was linked negatively with amplitude in the front currents. Negative symptom severity was linked negatively with the temporal current amplitude, according to research by Dr. Jerome Graus and his colleagues.
The higher the severity of hallucinations, the smaller the amplitude of the frontal current; the higher the PANSS (Positive and Negative Syndrome Scale) negative symptom score, the smaller the amplitude of the temporal currents, stated Dr. Graux.
The authors of the study wrote:
"The small amplitude of the frontal current in the present study suggests the involvement of a deep source in the frontal lobe, which might correspond to the involvement of the anterior cingulate cortex in the perception of human speech."
(Auditory hallucinations in schiophrenia tied to decreased brain current, retrieved on April 30, 2014 from http://www.clinicalpsychiatrynews.com/new/adult-psychiatry/...)
New research on visual and auditory hallucinations benefits individuals living with schizophrenia because as noted in my SharePost on anosognosia there is more information known about the lack of insight symptom than there is via studies on delusions and hallucinations.
The brain is the most complex organ and gives up its secrets reluctantly.
I will continue to report on the latest research studies in this field. This weekend I attend the American Psychiatric Association convention and will take back handouts from the poster sessions and exhibits to report on here at HealthCentral.
I'll end this month's news with information I already knew: Metformin may help combat antipsychotic-induced weight gain. A meta-analysis shows metformin appears to be the most effective pharmacological option for countering weight gain linked to the use of antipsychotic medications.
Metformin improves glucose tolerance in patients with type 2 diabetes.
The researchers pooled the effects of 40 studies that were published up to November 2013 and that evaluated 19 interventions for antipsychotic-induced weight gain. Metformin appeared to be the most effective of the medications studied, with an average body weight loss of 3.17 kg compared with individuals taking a placebo.
(Metformin may help combat antipsychotic-induced weight gain, retrieved on April 30, 2014 from http://psychnews.psychiatryonline.org/newsarticle.aspx/...)
Published On: April 30, 2014