Changes in regional brain volumes in social anxiety disorder following 12 weeks of treatment with escitalopram

Abstract

It has been suggested that antidepressants, including the selective serotonin reuptake inhibitors have neurotrophic effects. Nevertheless, the impact of treatment with a selective serotonin re-uptake inhibitor on regional brain volumes in social anxiety disorder has not been studied. 11 subjects with social anxiety disorder completed magnetic resonance imaging both before and after 12-weeks of treatment with 20 mg/day escitalopram. No increases in structural grey matter were found, but there were decreases in bilateral superior temporal cortex, vermis and the left cerebellum volumes following 12 weeks of treatment with escitalopram. These preliminary findings require replication to determine their reliability, and extension to determine whether or not they are disorder specific.

Gray Matter Abnormalities in Social Anxiety Disorder: Primary, Replication, and Specificity Studies

“…Resting state perfusion studies have reported both hyper- and hypo-perfusion in the cerebellum among subjects with SAD(47), and a Positron Emission Tomography study found anxiety induced in SAD patients to increase blood flow to the cerebellum(48). The aforementioned treatment study(23) reported decreased cerebellar volumes among SAD patients following three months of SSRI treatment, but because there was no control group, it is unclear whether the patients had abnormalities prior to being treated. Although the mechanisms are unclear, cerebellar abnormalities may increase vulnerability to anxiety states via modulation of arousal.…”

“…Some studies have included SAD subjects within anxiety groups but without differentiating them from other fear-based disorders(22). Finally, a recent treatment study reported volume decreases in the cerebellum and superior temporal cortex in SAD patients following 12 weeks of treatment with the selective serotonin reuptake inhibitor (SSRI) escitalopram(23). SSRIs however, are broadly efficacious for multiple anxiety and mood disorders, so the extent to which the changes index social anxiety is unknown.…”

A pilot study of gray matter volume changes associated with paroxetine treatment and response in social anxiety disorder

“…However, right hemisphere cerebellar volume was increased following paroxetine treatment. This is not only at odds with the above prediction but also with the aforementioned escitalopram treatment study (Cassimjee et al, 2010a) that showed a decrease in cerebellar volume post-treatment, albeit in a non-homologous left hemisphere region. The role of cerebellar abnormalities in the pathophysiology of anxiety remains unclear, although disturbances in autonomic regulation via circuits linking the cerebellar vermis to midbrain structures have been postulated as a mechanism (Baldacara et al, 2008).…”

“…Anatomical changes can be provide complementary information as unlike functional measures, detection of structural changes is not modulated by a subject’s current state or performance metrics. Only one study to our knowledge has directly probed treatment effects on neuroanatomy (Cassimjee et al, 2010b). In that study, reductions in left cerebellar and bilateral superior temporal volumes in 11 SAD patients were noted following 12 weeks of treatment with escitalopram, but correlations between anatomical changes and clinical course were not reported.…”

Recent advances in the brain imaging of social anxiety disorder

“…Another study found decreased grey matter (GM) volumes in the right inferior temporal gyrus and right parahippocampal gyrus in SAD (Liao et al ., ), and also an association between decreased volumes and increased symptom severity. The third study found that treatment with escitalopram led to decreased GM volumes in the bilateral superior temporal cortex, vermis and left cerebellum (Cassimjee et al ., ).…”