In psychosis, patients experience hallucinations, such as hearing voices, and hold delusional beliefs
Two
brain systems have been found to function improperly in people experiencing
psychosis, where they have trouble distinguishing between what is real and what
is not, according to a new research led by Stanford University, US.
These
systems were found to be -- one, a ‘filter’ directing attention towards what is
important externally and internally, and two, a ‘predictor’ involved in
anticipating rewards.
The
filtering system, or the salience network, helps us dismiss irrational thoughts
so that we can focus on what’s real and meaningful to us, such as paying
attention to traffic while driving, researchers explained.
The
reward predicting system, driven by dopamine, is critical to anticipating what
will be rewarding or important, they said.
Together,
they malfunction in a way such that thoughts not linked to reality capture the
brain’s cognition networks, said Vinod Menon, a professor of psychiatry and
behavioural sciences, Stanford University, US.
“This
process derails the normal functioning of cognitive control, allowing intrusive
thoughts to dominate, culminating in symptoms we recognise as psychosis,” said
Menon, senior author of the study published in the journal ‘Molecular Psychiatry’.
In
psychosis, patients experience hallucinations, such as hearing voices, and hold
delusional beliefs, such as thinking that people who are not real exist, the
researchers said. The state is known to occur either on its own, or as a
symptom of mental illnesses such as bipolar disorder and schizophrenia.
For
the study, the researchers analysed brain scans of people aged 6-39 years with
psychosis. They found the two brain regions contributing the most to psychosis
were the anterior insula, which is a key part of the salience or ‘filtering’
network, and the ventral striatum, which is the ‘reward predicting’ one.
The
findings provide a good model for understanding the development and progression
of schizophrenia, according to lead author Kaustubh Supekar, clinical associate
professor of psychiatry and behavioral sciences.
“In
schizophrenia, by the time of diagnosis, a lot of damage has already occurred
in the brain, and it can be very difficult to change the course of the
disease,” said Supekar.
“What
we saw is that, early on, functional interactions among brain regions within
the same brain systems are abnormal,” he said adding, “The abnormalities do not
start when you are in your 20s; they are evident even when you are seven or
eight.”
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