TORONTO, Jan. 10, 2012 /CNW/ - In a new study from the Centre for
Addiction and Mental Health (CAMH), people with schizophrenia showed
greater brain activity during tests that induce a brief, mild form of
delusional thinking. This effect wasn't seen in a comparison group
The study appears in the December issue of Biological Psychiatry.
"We studied a type of delusion called a delusion of reference, which
occurs when people feel that external stimuli such as newspaper
articles or strangers' overheard conversations are about them," says
CAMH Scientist Dr. Mahesh Menon, adding that this type of delusion
occurs in up to two-thirds of people with schizophrenia. "Then they
come up with an explanation for this feeling to make sense of it or
give it meaning."
The study was an initial exploration of the theory that the overactive
firing of dopamine neurons in specific brain regions is involved in
converting neutral, external information into personally relevant
information among people with schizophrenia. This may lead to symptoms
of delusions. "We wanted to see if we could find a way to 'see' these
delusions during Magnetic Resonance Imaging scanning," says Dr. Menon.
The senior author of the study is Dr. Shitij Kapur, dean and head of
the Institute of Psychiatry in the U.K.
A better understanding of the brain activity and thinking patterns
leading to delusions could point the way to more focused treatment
options, the researchers say.
The study results are based on 14 people with a schizophrenia diagnosis
and 15 people in a control group. Participants were presented with 60
statements while in an MRI scanner. For each statement, they were asked
whether they felt it was about them.
Twenty statements were specific to each participant, and included
details taken from initial screening interviews. The remaining 40
statements were generic, and evenly divided between statements that
were neutral ("he collects CDs") or that had an emotional connotation
("everybody hates her").
People with schizophrenia and in the comparison group were just as
likely to agree that personalized statements were about themselves.
However, those with schizophrenia were significantly more likely to say
that the generic statements referred to them. "The participants with
schizophrenia had a harder time telling the difference between
personally relevant and non-relevant statements," says Dr. Menon.
When participants agreed a statement was personal, specific brain areas
"lit up" in the scanner, indicating activity in these areas. Among
those with schizophrenia, this brain activity occurred even when they
said "no" to a statement that was not about them, suggesting that they
had greater difficulty in distinguishing what was self-relevant to what
The brain regions with activity included the cortical midline structures
(such as the medial prefrontal cortex and anterior cingulate cortex),
as well as regions like the insula and ventral striatum. These areas
are connected to the brain's dopamine regions, or are involved in
introspective and emotional processing - which fit the researchers'
The control group, which was more likely to respond "no" to irrelevant
statements, showed little brain activity in response to generic
Even when people with schizophrenia agreed a generic statement was not about them, they took longer to respond and the difference in certain
brain activity levels was not as great as in the control group.
Once these processes are better understood, approaches such as
attentional retraining therapy, or repetitive transcranial magnetic
stimulation (rTMS) may be explored possible treatments of delusions.
rTMS is a non-invasive form of brain stimulation currently used for
Further research is needed to expand on these initial findings. For
instance, patients in this study were all taking anti-psychotic
medication. Other studies could look at people early in illness who are
not on medication, and could also follow people over time, before and
after they take medication.
It is estimated that one person in 100 develops schizophrenia, a
disturbance of the brain's functioning that can seriously impact the
way people think, feel and relate to others. Some people diagnosed with
schizophrenia recover almost completely, while others need treatment
and support for the rest of their lives.
The Centre for Addiction and Mental Health (CAMH) is Canada's largest
mental health and addiction teaching hospital, as well as one of the
world's leading research centres in the area of addiction and mental
health. CAMH combines clinical care, research, education, policy
development and health promotion to help transform the lives of people
affected by mental health and addiction issues.
CAMH is fully affiliated with the University of Toronto, and is a Pan
American Health Organization/World Health Organization Collaborating
SOURCE Centre for Addiction and Mental Health
For further information:
Media Contact: Michael Torres, Media Relations, CAMH; 416-595-6015