Anxiety is associated with striatal dopamine transporter availability in newly diagnosed untreated Parkinson's disease patients.
BACKGROUND
Anxiety is a common non-motor symptom among patients with Parkinson's disease (PD). Although the etiology of anxiety in PD is likely to be multifactorial, a dysfunction in the dopaminergic system might be implicated in its pathogenesis. The aim of our study was to investigate a possible dopaminergic mechanism involved in anxiety in newly diagnosed never-medicated PD patients using SPECT and ¹²³I-FP-CIT as the dopamine transporter ligand.


METHODS
Thirty-four newly diagnosed, untreated PD patients with asymmetric motor symptoms were included in the study: 17 patients with right- and 17 with left-motor onset, matched for age, disease duration and motor disability constituted the group. They were all evaluated for anxiety and depression and underwent an SPECT with ¹²³I-FP-CIT. Dopamine transporter (DAT) availability values for right and left caudate and putamen were calculated and compared between patients with and without anxiety. Regression analyses were also performed in order to correlate DAT availability with the severity of the anxiety symptoms.


RESULTS
Comparison between PD patients with and those without anxiety revealed significant differences of DAT availability in all the examined regions except the right putamen. In the group of patients considered as a whole, a significant correlation was found between increased anxiety severity and decreased DAT availability in right caudate.


CONCLUSIONS
We reported an association between nigrostriatal DAT availability deficits and anxiety symptoms in newly diagnosed, untreated PD patients. Our results suggest that hypofunction of the nigrostriatal dopaminergic system may represent one of the functional anomalies involved in anxiety in PD from the earliest stages of disease and irrespective of any therapy.
University Federico II, Department of Neurological Science, Naples, Italy.
Roberto
R
Erro
Sabina
S
Pappatà
Marianna
M
Amboni
Caterina
C
Vicidomini
Katia
K
Longo
Gabriella
G
Santangelo
Marina
M
Picillo
Carmine
C
Vitale
Marcello
M
Moccia
Flavio
F
Giordano
Arturo
A
Brunetti
Maria Teresa
MT
Pellecchia
Marco
M
Salvatore
Paolo
P
Barone
D000368:Aged; D001007:Anxiety / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology*; D016022:Case-Control Studies; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000000981:diagnostic imaging; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
D050483:Dopamine Plasma Membrane Transport Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane