Sydney: A world first study revealing the presence of two antibodies in a sub-group of children experiencing their first episode of psychosis affirms a longstanding recognition that auto-immune disorders play a significant role in psychiatric illness. Antibodies defend the body against bacterial, viral, and other invaders but sometimes the body makes antibodies that attack healthy cells. In these cases, autoimmune disorders develop. These include conditions such as multiple sclerosis (MS), rheumatoid arthritis and Type 1 diabetes. This 'immune hypothesis' is supported by new research in the current issue of Biological Psychiatry.
from the Kids Research Institute at the Children's Hospital, Westmead,
and the University of Sydney detected antibodies to the dopamine D2
receptor or the N-methyl-D-aspartate (NMDA) glutamate receptor among
eight out of 43 children experiencing their first episode of psychosis,
but no such antibodies in healthy children.
Both are key neural signaling proteins previously been implicated in psychosis.
antibodies we have detected in children having a first episode of acute
psychosis suggest there is a distinct subgroup for whom autoimmunity
plays a role in their illness," says the University of Sydney's Dr Fabienne Brilot, the senior author on the paper and Head of the Neuroimmunology Group at The Children's Hospital at Westmead in Sydney.
finding suggests that better interventions are possible, providing hope
that major disability can be prevented for the subset of children
experiencing acute psychosis with antibodies," Brilot adds.
is a chemical messenger aiding the transmission of signals in the brain
and other areas of the body. Regulating its actions plays a crucial
role in mental and physical health.
Dopamine acts on receptors
tailored specifically for it. The dopamine-2 receptor (D2R) is one of
five subtypes of mammalian dopamine. Increasing knowledge of the roles
of dopamine receptor subtypes raises the hope that more selective drugs
will be developed.
Abnormalities in dopaminergic neurotransmission
play a key role in the pathogenesis of psychosis. Many drugs affect
dopamine transmission directly by either blocking or stimulating its
Many antipsychotics show varying affinities for the
different dopamine receptors but blockade of the dopamine-2 receptor
(D2R) specifically has proved to be indispensable in the clinical
management of psychosis.
While less well established than
dopamine, it is also likely that glutamatergic dysfunction also plays a
role in psychotic disease.
This suggests that specific pathologies
and processes affecting D2R and the glutamatergic N-methyl-D-aspartate
receptor (NMDAR) could define biological subgroups and may be involved
in the pathogenesis of psychosis and other psychiatric illnesses such as
"There is a pressing need in psychiatry to
establish biologically based disease subtypes, which might allow for
more specific diagnosis and effective intervention," says Dr Brilot.
findings contribute further understanding of the biology of psychiatric
and neurological diseases and whether autoantibodies detected in a
subgroup of patients can trigger psychiatric disorders.
research will reveal whether these antibodies are the mark of a
clinically relevant subset of patients and, if so, whether
immunosuppressive therapies can effectively treat children with these
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