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.
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