Dopamine transporter density in young patients with schizophrenia assessed with [¹²³]FP-CIT SPECT

Abstract 

Disturbances in the dopamine (DA) system are thought to play a major role in schizophrenia. Amphetamine-induced release of endogenous DA is shown to be enhanced in schizophrenia, as is striatal [¹⁸F]FDOPA uptake in the striatum. It is not clear if the density of DA neurons is altered in schizophrenia. By studying the DA transporter with [¹²³I]FP-CIT single photon emission computed tomography (SPECT), the density of nigrostriatal dopaminergic cells can be studied.

Using [¹²³I]FP-CIT SPECT, DA transporter density in the striatum was studied in 36 young patients with schizophrenia. Ten patients were antipsychotic (AP)-naive, 15 were treated with olanzapine, eight with risperidone and three were AP-free. A control group of 10 age-matched volunteers was included.

Striatal [¹²³I]FP-CIT binding was not significantly different between AP-naive patients (2.87), patients treated with olanzapine (2.76), patients treated with risperidone (2.76), AP-free patients (2.68) and controls (2.82) (F=0.07,p=0.98). Unexpectedly, striatal [¹²³I]FP-CIT binding in females was significantly higher than in males (3.29 and 2.70, respectively; t=−2.56, p=0.014).

Concluding, functional changes in the dopaminergic system in schizophrenia are not likely to be reflected in a change in DA transporter density. Moreover, DA transporter density does not seem to be altered by AP medication.

Keywords: Antipsychotic medication, Dopamine transporter, Gender, Schizophrenia, Single photon emission computed tomography (SPECT)