[Striatal dopamine transporter density decrease in first episode schizophrenic patients treated with risperidone].
Extrapyramidal symptoms and Parkinsonism (PS) are side effects commonly observed with antipsychotic treatment. However, about 24% of never-treated schizophrenic patients may suffer from PS, which contrast with that 1% observed from the general population. 123I-FP-CIT SPECT has probe useful to differentiate degenerative from non-degenerative PS, so it could be interesting using it for establishing the functional state of presynaptic dopamine neurons of these patients.


OBJECTIVE
To determine the dopamine transporter binding (DAT) in a homogeneous group of first-episode schizophrenic patients.


METHODS
An open, transversal study. Thirty schizophrenic in-patients and 15 healthy subjects were recruited. Patients were treated with similar doses of risperidone and all subjects were scanned with 123I-FP-CIT. Extrapyramidal symptoms and psychopathological status was assessed by Simpson-Angus, CGI and PANSS. Semi-quantitative analyses of SPECT images were performed using ROIs placed in caudate nucleus, anterior, medium and posterior putamen and occipital cortex.


RESULTS
Whole striatum 123I-FP-CIT binding ratio was significantly lower in patients than healthy subjects (t = 2.56, p < 0.014). This was observed in whole putamen (t = 2.66, p < 0.011), anterior (t = 2.35, p < 0.023), medium (t = 2.38, p < 0.022) and posterior putamen (t = 2.09, p < 0.042). No differences were observed in caudate nucleus (t = 1.81, p = 0.076). Females obtained higher binding ratios than males (t = -3.13, p < 0.003). No correlation was observed between 123I-FP-CIT binding ratios and clinical scales.


CONCLUSIONS
In our series, first episode schizophrenic patients treated with risperidone have a decrease striatal DAT binding assessed with 123I-FP-CIT SPECT. This alteration could be related to their own schizophrenia disease or be secondary to the antipsychotic treatment.
Mateos
J J
JJ
Servicio de Medicina Nuclear, Hospital Clínico de Barcelona, Universidad de Barcelona, España. 32395jmf@comb.es
Lomeña
F
F
Parellada
E
E
Font
M
M
Fernández
E
E
Pavia
J
J
Prats
A
A
Bernardo
M
M
D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000494:pharmacology*; D001480:Basal Ganglia Diseases / Q000139:chemically induced / Q000000981:diagnostic imaging; D002421:Caudate Nucleus / Q000737:chemistry / Q000000981:diagnostic imaging; D003342:Corpus Striatum / Q000737:chemistry* / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D018492:Dopamine Antagonists / Q000009:adverse effects / Q000494:pharmacology*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010302:Parkinson Disease, Secondary / Q000139:chemically induced / Q000000981:diagnostic imaging; D017729:Presynaptic Terminals / Q000737:chemistry*; D011699:Putamen / Q000737:chemistry / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D018967:Risperidone / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism; D012737:Sex Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes / Q000493:pharmacokinetics
D014150:Antipsychotic Agents; D018492:Dopamine Antagonists; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D009419:Nerve Tissue Proteins; D019275:Radiopharmaceuticals; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D018967:Risperidone