Altered Brain Activity In Schizophrenia May Direct Focus On Self
ScienceDaily (Jan. 20, 2009) — Schizophrenia may blur the boundary between internal and external realities by overactivating a brain system that is involved in self-reflection, and thus causing an exaggerated focus on self, a new MIT and Harvard brain imaging study has found.
The traditional view of schizophrenia is that the disturbed thoughts, perceptions and emotions that characterize the disease are caused by disconnections among the brain regions that control these different functions.
But this study, appearing Jan. 19 in the advance online issue of the Proceedings of the National Academy of Sciences, found that schizophrenia also involves an excess of connectivity between the so-called default brain regions, which are involved in self-reflection and become active when we are thinking about nothing in particular, or thinking about ourselves.
“People normally suppress this default system when they perform challenging tasks, but we found that patients with schizophrenia don’t do this,” said John D. Gabrieli, a professor in the McGovern Institute for Brain Research at MIT and one of the study’s 13 authors. “We think this could help to explain the cognitive and psychological symptoms of schizophrenia.”
Gabrieli added that he hopes the research might lead to ways of predicting or monitoring individual patients’ response to treatments for this mental illness, which occurs in about 1 percent of the population.
Schizophrenia has a strong genetic component, and first-degree relatives of patients (who share half their genes) are 10 times more likely to develop the disease than the general population. The identities of these genes and how they affect the brain are largely unknown.
The researchers thus studied three carefully matched groups of 13 subjects each: schizophrenia patients, nonpsychotic first-degree relatives of patients and healthy controls. They selected patients who were recently diagnosed, so that differences in prior treatment or psychotic episodes would not bias the results.
Read the whole study.
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The delusional brain
Category: Neuroscience • Psychiatry
Posted on: January 20, 2009 12:52 PM, by MoDelusions are pathological beliefs which persist despite clear evidence that they are actually false. They can vary widely in content, but are always characterized by the absolute certainty with which they are held. Such beliefs reflect an abnormality of thought processes; they are often bizarre and completely unrelated to conventional cultural or religious belief systems, or to the level of intelligence of the person suffering from them.
The delusions experienced by psychiatric patients are sometimes categorized according to their theme. For example, schizophrenics often suffer from delusions of control (the belief that an external force is controlling their thoughts or actions), delusions of grandeur (the belief that they are a famous rock star or historical figure) or delusions of persecution (the belief that they are being followed, attacked or conspired against).
Although often associated with psychiatric disorders, delusions can also occur as a symptom of neurodegenerative disorders, and improved diagnostic methods have led to an increase in the identification of brain damage in patients who suffer from them. To date, however, there has not been an all-encompassing theory of how the brain generates delusions. Now though, Orrin Devinsky, a professor of neurology, neurosurgery and psychiatry at New York University, proposes that delusions are generated by a combination of right hemisphere damage and left hemisphere hyperactivity.
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