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Howes O.D. Dopamine synthesis capacity in patients with treatment-resistant schizophrenia.

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et al. Presynaptic dopamine dysfunction in people at ultra-high risk for psychosis: Findings in a second cohort.

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et al. Reduced prefrontal activity predicts exaggerated striatal dopaminergic function in schizophrenia.

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et al. Regional dopamine synthesis in patients with schizophrenia using L-[beta-11C]DOPA PET.

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McGuire P.K.

Kapur S.

Howes O.D. Dopamine synthesis capacity in patients with treatment-resistant schizophrenia.

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Brugger S.

Raffin M.

Barker G.J.

Lythgoe D.J.

McGuire P.K.

et al. Anterior cingulate glutamate levels related to clinical status following treatment in first-episode schizophrenia.

Approximately a third of patients with schizophrenia show a limited response to antipsychotic medication (). This might be due to distinct neurochemical abnormalities in a subgroup of patients, but to date there is little evidence to support this hypothesis (). Increased presynaptic dopamine synthesis has consistently been reported in patients with schizophrenia (). In a recent 3,4-dihydroxy-6-[F]fluoro-L-phenylalanine (F-DOPA) positron emission tomography (PET) study, we found that, although an increase in striatal dopamine synthesis capacity was evident in patients who had responded to antipsychotic treatment, there was no increase in patients who were treatment-resistant (). In a separate proton magnetic resonance spectroscopy (H-MRS) study in first-episode psychosis, we found elevated glutamate levels in the anterior cingulate cortex in patients who had persistent psychotic symptoms despite antipsychotic treatment, relative to patients in whom there had been a good symptomatic response ().