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Oades, R. D., Henning,
U., Klimke, A., Rao, M.L., Hesse, A., Bender, S., & Sartory, G.,
(2001). Monoamine metabolism, subtypes
of schizophrenia and neuroleptic medication. World Journal of Biological
Psychiatry, 2, 286..
One current hypothesis on the dopamine (DA) contribution to schizophrenia
relates to under- and over-activity in patient groups expressing different
symptom clusters (i.e. in mesocortical/ mesolimbic systems based on
the role of tonic/phasic, extra/intrasynaptic DA activity
[1]).
Here serum monoamines, metabolites and DA-D2 binding were studied in
relation to 4 PCA symptom-dimensions and medication of 63 patients with
schizophrenia and 63 healthy subjects participating in a neuropsychological
study.
(1) The paranoid (vs. nonparanoid) dimension
was associated with lower levels of utilization of both DA (HVA/DA)
and NA (MHPG/NA), presumably reflecting in part responsiveness to sub-chronic
treatment and higher DA-D2 occupancy [2]
(irrespective of covariation with chlorpromazine equivalents).
(2) Those with marked thought disorder
(factor-1) had a low HVA/5HIAA and HVA/MHPG ratios attributable to low
HVA levels.
(3) Strong ideas-of-reference (factor-3)
related to high turnovers of DA and 5-HT (5-HIAA / 5-HT) and an increased
HVA/5-HIAA ratio.
(4) Clozapine, olanzapine and sertraline
treatment were associated with higher levels of HVA, DA and HVA/5-HIAA
vs. risperidone and more typical antipsychotic drugs that produced raised
levels of prolactin and estimated DA D2 central occupancy
[2]
Atypical medication may improve monoamine imbalance (e.g. HVA/5-HIAA)
in positive/negative symptoms and thought disorder but not with respect
to ideas-of-reference.
1. Grace, A.A., (1993) Cortical regulation
of subcortical dopamine systems and its possible relevance to schizophrenia.
Journal of. Neural Transmission., 91, 111-134
2. Oades et al., (2000). Neuropsychological
and conditioned blocking performance in patients with schizophrenia:
assessment of the contribution of neuroleptic dose, serum levels and
dopamine D2-receptor occupancy. Behavioural Pharmacology, 11,
317-330.
Support: DFG (OA 1/4-1&2)
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