The striatal dopamine transporter in first-episode, drug-naive schizophrenic patients: evaluation by the new SPECT-ligand[99mTc]TRODAT-1

Following the current hypothesis that acute schizophrenic psychotic
illness is associated with a triatal ‘hyperdopaminergic state’,
presynaptic integrity and dopamine transporter (DAT) density in
first-episode, neuroleptic-naive schizophrenic patients was
measured by single-photonemission- tomography (SPECT) and compared
with that in healthy control subjects. A new SPECT-ligand for
assessment of the striatal DAT, the Technetium-99m-labelled tropane
TRODAT-1 ([99mTc]TRODAT-1), was used. Ten inpatients suffering from
a first acute schizophrenic episode and 10 age- and sex-matched
healthy control subjects underwent SPECT with [99mTc]TRODAT-1. On
the day of SPECT, psychopathological ratings were performed with
the Brief Psychiatric Rating Scale (BPRS), the Positive and
Negative Syndrome Scale (PANSS) and Schedule for Assessment of
Negative Symptoms (SANS). Patients had not previously received any
neuroleptic or antidepressant medication. Mean specific TRODAT-1
binding in the striatum did not differ significantly between the
patient and the age- and sex-matched control group (1.25 vs. 1.28).
Variance was significantly higher in the patient group. The data
obtained with the new ligand in first-episode, drug-naive
schizophrenic patients are in line with the PET results from the
group of Laakso et al. in a comparable patient sample.
[99mTc]TRODAT-1 seems to be a valuable new SPECTligand in the
evaluation of the presynaptic site of the striatal dopaminergic
synapse in schizophrenia.