Scientists from King's College London and the University of
Roehampton have identified a key mechanism in the brain which might
be associated with the onset and development of psychosis.
Using a Magnetic Resonance Imaging (MRI) technique they found
that 52 young people deemed to be at ultra high risk of psychosis
had increased or 'hyperactive' levels of blood flow compared to 27
healthy controls in the hippocampus, striatum and midbrain - all
brain regions that are particularly implicated in the onset of
psychotic disorders like schizophrenia.
This study is one of the first in humans to confirm results from
animal research, which has already shown that increased activity in
these brain regions drives the development of psychosis.
In the study, funded by the Medical Research Council, the
researchers also repeated the MRI scans after 18 months to examine
how blood flow levels had changed. In participants whose presenting
symptoms had resolved, the researchers found that resting blood
flow levels in the hippocampus had decreased to the levels seen in
healthy participants. This suggests that normalisation of blood
flow in the hippocampus may underlie clinical improvement in these
participants.
Professor Paul Allen from the Institute of Psychiatry,
Psychology & Neuroscience (IoPPN) at King's College London and
the University of Roehampton said: "Our research identified
significant differences in brain blood flow between healthy people
and those at ultra high risk of psychosis. These differences help
us understand the neurobiological mechanisms that underlie the
development of psychosis."
Professor Philip McGuire, also from the IoPPN at King's College
London, added: "These findings are also important in terms of
clinical practice. They underline the potential of brain scanning
to help clinicians predict whether people who are at increased risk
of psychosis will go on to develop a disorder or whether they will
recover.
"In addition, understanding what is happening in the brain at
this stage also informs the ongoing development of new treatments
designed to prevent the development of psychotic disorders."
The paper, Resting Hyperperfusion of the Hippocampus, Midbrain, and Basal
Ganglia in People at High Risk for Psychosis, is published in
the American Journal of Psychiatry.