Dopamine transporter binding in social anxiety disorder: the effect of treatment with escitalopram

Abstract

Social anxiety disorder (SAD) is characterised by fear of social or performance situations where the individual is exposed to unfamiliar people or to possible scrutiny by others. The literature on dopamine ligands and dopamine genotypes in SAD is however inconsistent. In this study we measured the effects of SSRI pharmacotherapy on dopamine transporter (DAT) binding in patients with SAD, also addressing variability in DAT genotype. Adult subjects meeting DSM-IV criteria for generalised SAD were studied before and after 12 weeks of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI) escitalopram. DAT single photon emission computed tomography (SPECT) using (123)I-FP-CIT was performed at baseline, and repeated at 12 weeks. Striatal DAT binding was analysed for changes following therapy, and for correlations with clinical efficacy, in the whole group as well as for a subgroup with the A10/A10 DAT genotype. The study included 14 subjects (9 male, 5 female) with a mean (SD) age of 41 (±13) years. The subjects' Liebowitz Social Anxiety Scale (LSAS) score was significantly decreased following pharmacotherapy. In the combined group the left caudate and left putamen showed clusters of increased DAT binding after therapy. The left caudate changes were also observed in the subgroup of 9 A10/A10 homozygotes. However no correlation was found between improved symptoms and DAT binding. The changes found in DAT binding in the caudate and putamen may be due to serotonergic activation of dopamine function by SSRI therapy. This is consistent with previous work indicating decreased DAT binding in SAD, and increased DAT binding after SSRI administration.

Extrastriatal dopamine D2-receptor availability in social anxiety disorder

“…Coordinates are reported in the Montreal Neurological Institute standard space. investigating the DA system in SAD have provided only partial support for this hypothesis (van der Wee et al, 2008;Tiihonen et al, 1997;Warwick et al, 2012). Previous studies of striatal D2-R have reported no differences (Schneier et al, 2009), or lower levels in patients (Schneier et al, 2000), as compared to the present results of elevated extrastriatal D2-R availability.…”

Nuclear Neuroimaging in Social Anxiety Disorder: A Review

“…Effects of therapy on nuclear dopaminergic measures have also been investigated. In work investigating the effect of escitalopram on DAT binding, researchers reported a therapy-related increase in striatal DAT binding measured with 123 I-ioflupane SPECT, although no correlation was found between symptom improvement and binding (35). Posttherapy increases in caudate DAT binding in that study were also seen in a subgroup of patients homozygous for the A10 DAT genotype.…”

Hyper-Connectivity of Subcortical Resting-State Networks in Social Anxiety Disorder

“…By probing the striatum (caudate and putamen), globus pallidus, thalamus, amygdala and periaqueductal gray, our study provides an important contribution to the literature and may prove useful for developing and improving treatment strategies. Unlike most of the published fcMRI studies on SAD, we employed a drug naïve sample in the current study because of the known influence of pharmacotherapy (Warwick et al, 2012).…”