ABSTRACTS - World Psychiatric Association

attempted suicides, primary outcome) with a decrease in Nuremberg
(500,000 inhabitants) of 24% after two intervention years and a further
decrease in the follow-up years. This concept and the intervention
materials have been adopted and refined by many regions in 17
countries within the European Alliance against Depression, funded
by the European Commission.
US11.
BRAIN IMAGING IN PSYCHIATRY: RECENT
PROGRESS AND CLINICAL IMPLICATIONS
US11.1.
ADVANCEMENTS IN MOLECULAR POSITRON
EMISSION TOMOGRAPHY IMAGING
FOR PSYCHIATRIC RESEARCH
L. Farde
Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm; AstraZeneca R&D, Södertalje, Sweden
The imaging technology positron emission tomography (PET) is used
to trace radiolabeled molecules in the human brain. Molecular imaging
is based on the development of suitable radioligands for neuroreceptors,
enzymes or transport proteins. The radioligand can then be
used in research on the pathophysiology of brain disorders or in clinical
pharmacology to measure the occupancy of drug treatments. A
related approach is to develop radioligands that bind to biomarkers
for pathophysiology, such as amyloid in Alzheimer’s disease. Work on
new proteins is a particular challenge in neuroscience, because
approximately half of the human genes are expressed in brain. This
availability of numerous new proteins provides vast opportunities for
new drug treatment. However, using the suitable radioligands so far
developed for molecular imaging, only about 25 central nervous system
proteins can be examined by PET. The field benefits from the
present industrial investments in PET imaging and access to chemistry
resources, which facilitates more effective developments of new radioligands.
Interestingly, these efforts may in addition provide academia
with new tools to reveal the functional role of recently discovered proteins
in the human brain. Such research benefits from the advancements
of the PET technology. The high resolution research tomography
(HRRT) and recent implementation of improved image reconstruction
software provides brain imaging at a resolution of about 1.6
mm. This high resolution allows for detailed mapping of proteins and
disease biomarkers in the human brain. Moreover, advanced image
analysis, including statistical methods for recognition of patterns of
protein distribution in brain, are now developed to take benefit of the
vast amount of information generated by a single PET measurement.
Taken together, these methodological advancements pave the way for
a new era of PET imaging in psychiatric research.
US11.2.
ADVANCES IN WHITE MATTER IMAGING
AND THEIR APPLICATION TO SCHIZOPHRENIA
M.E. Shenton, M. Kubicki, T. Kawashima, D. Markant, T. Ngo,
R.W. McCarley, C.-F. Westin
Departments of Psychiatry and Radiology, Brigham and Women’s
Hospital and Harvard Medical School, Boston, MA; Department
of Psychiatry, Veterans Affairs Boston Healthcare System
and Harvard Medical School, Brockton, MA, USA
While a great deal of progress has been made over the last two decades
in identifying gray matter abnormalities in schizophrenia, only recently
has the same level of scrutiny been applied to white matter. Moreover,
recent longitudinal magnetic resonance imaging (MRI) studies
demonstrate progressive changes in gray matter in both temporal and
frontal cortices, following illness onset. In contrast, far less is known
about the evolution and progression of white matter abnormalities, or
about the integrity of white matter connections, particularly those that
connect the frontal and temporal lobes, tracts that have long been
thought to be abnormal in schizophrenia. With the development of
diffusion tensor imaging, we are now able to investigate white matter
abnormalities. Here, we report recent findings using region of interest
and tractography methods that show fronto-temporal abnormalities
in chronic schizophrenia, including uncinate fasciculus, fornix, and
cingulum bundle. We also present findings in schizotypal personality
disorder (SPD), first episode patients diagnosed with schizophrenia
(FESZ), and first episode patients diagnosed with bipolar disorder
with psychotic features (FEBP). For SPD and first episode patients,
we report uncinate but not cingulum bundle abnormalities. These
findings suggest that cingulum bundle abnormalities are not present in
SPD or at first episode, but are evident in chronic schizophrenia. In
addition, findings suggest that uncinate fasciculus abnormalities may
not specific to schizophrenia or to SPD, as they are evident in FEBP
and FESZ. Further studies are needed that follow changes over time
in order to further characterize white matter abnormalities in schizophrenia
and bipolar disorder.
US11.3.
NEUROIMAGING IN PSYCHOSIS: INTEGRATION
OF DATA ACROSS MODALITIES
P. McGuire
Institute of Psychiatry and OASIS, London, UK
Recent neuroimaging studies have provided new information about
the mechanisms underlying the development of psychosis. Volumetric
magnetic resonance imaging (MRI) and diffusion tensor imaging
(DTI) studies have clarified the extent to which grey and white matter
abnormalities are evident before and after the onset of psychosis,
while the application of functional MRI (fMRI) has indicated the
neural basis of impaired executive functions, memory and salience
processing in the early phase of the disorder. Similarly, studies using
positron emission tomography (PET) and MR spectroscopy have
revealed how dopamine and glutamate transmission are altered in the
prodromal phase of psychosis. However, these studies have been conducted
separately, and the relationship between the structural, functional
and neurochemical findings they have identified is unclear.
Using different neuroimaging techniques in the same subjects provides
a means of addressing this issue. We have employed this
approach in subjects with prodromal signs of psychosis. In a study
combining F-dopa PET with fMRI, there was a significant correlation
between elevated striatal dopamine function in prodromal subjects
and altered prefrontal activation during a verbal fluency task. In a
second study that combined volumetric MRI and MR spectroscopy,
reduced medial temporal and prefrontal grey matter volume in prodromal
subjects was correlated with the degree to which glutamate
levels in the thalamus were reduced. These initial results suggest that,
although logistically difficult, multi-modal neuroimaging has the
potential to advance our understanding of the pathophysiology of
psychiatric disorders.
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