Brain GABA levels in patients with bipolar disorder.

PURPOSE: A growing body of research supports an important role for GABA in the pathophysiology of bipolar and other mood disorders. The purpose of the current study was to directly examine brain GABA levels in a clinical sample of bipolar patients. GENERAL METHODS: We used magnetic resonance spectroscopy (MRS) to examine whole brain and regional GABA, glutamate and glutamine in 13 patients with bipolar disorder compared to a matched group of 11 healthy controls. FINDINGS: There were no significant differences in GABA, glutamate or glutamine between patients and controls. CONCLUSIONS: Further research is needed to better characterize the GABAergic and glutamatergic effects of pharmacotherapy, anxiety comorbidity and clinical state in bipolar disorder.

High-field MRS study of GABA, glutamate and glutamine in social anxiety disorder: response to treatment with levetiracetam.

OBJECTIVE: Abnormalities in brain gamma-aminobutyric acid (GABA) and glutamate may be relevant to the underlying pathophysiology of anxiety disorders including social anxiety disorder (SAD). METHODS: We used proton magnetic resonance spectroscopy (pMRS) to examine whole brain and regional GABA, glutamate and glutamine in patients (N=10) with SAD at baseline compared to a matched group of healthy controls (HC), and changes following 8 weeks of pharmacotherapy with levetiracetam. RESULTS: For SAD subjects, there were significantly higher whole brain levels of glutamate and glutamine, though no significant differences in GABA. In the thalamus, glutamine was higher and GABA lower for SAD subjects. There was a significant reduction in thalamic glutamine with levetiracetam treatment. CONCLUSION: Our findings provide preliminary support for impaired GABAergic and overactive glutamatergic function in social anxiety disorder and the potential relevance of changes in these systems for the anxiolytic response to levetiracetam.

Aripiprazole as augmentation treatment of refractory generalized anxiety disorder and panic disorder.

INTRODUCTION: Individuals with anxiety disorders often remain symptomatic despite treatment with a first-line pharmacologic agent. More research examining pharmacotherapy augmentation strategies to improve outcomes is needed. METHODS: In an 8-week, open-label, prospective augmentation study, we examined the efficacy and tolerability of the novel antipsychotic agent aripiprazole for adult outpatients with generalized anxiety disorder (n=13) or panic disorder (n=10) who remained symptomatic despite treatment for at least 8 weeks with an adequate (or maximally tolerated) dose of typical pharmacotherapy. RESULTS: Aripiprazole augmentation was associated with a significant reduction in Clinical Global Impressions-Severity scores (paired t=4.41, df=22, P<.001) in the intent-to-treat sample of 23 individuals. Three subjects (13%) discontinued due to sedation, chest discomfort, and restlessness, respectively. CONCLUSION: These data provide preliminary evidence that aripiprazole may be a useful augmentation strategy for individuals with generalized anxiety disorder or panic disorder who show a limited response to initial pharmacotherapy.

Open-label support for duloxetine for the treatment of panic disorder.

Panic disorder with or without agoraphobia is a common, often chronic and refractory anxiety disorder. Although a number of pharmacotherapies are now indicated for panic disorder, many patients do not respond to available interventions. We hypothesized that duloxetine, a serotonin-norepinephrine reuptake inhibitor (SNRI) that has greater initial noradrenergic effects than venlafaxine, would have broad efficacy for individuals with panic disorder. Fifteen individuals with panic disorder with or without agoraphobia received 8 weeks of open label duloxetine flexibly dosed from 60 to 120 mg per day. Duloxetine treatment resulted in significant anxiolysis as measured by the primary outcome measure, the Panic Disorder Severity Scale (PDSS) (paired t(df) = 4.02(14), P= 0.0013), as well as measures of generalized anxiety, depression and quality of life (all P < 0.05). Although definitive conclusions are limited due to its small open-label nature, this first prospective study provides preliminary support for the efficacy of duloxetine for panic disorder and suggests larger randomized controlled study is warranted.

A comparison of emotional approach coping (EAC) between individuals with anxiety disorders and nonanxious controls.

Emotional regulation deficits are described as a core component of anxiety disorders (ADs), yet there remains a paucity of data examining this issue in patients diagnosed with ADs. We hypothesized that help-seeking individuals with ADs would report lower levels of emotional approach coping (EAC), which includes emotional processing (EP) and emotional expression (EE), than nonanxious controls. Diagnostic interviews and a validated self-report scale assessing emotional approaches to coping (emotional approach coping scale [EACS]) were administered to 101 nonanxious controls and 92 patients with a primary AD (29 generalized anxiety disorder, 40 social anxiety disorder, and 23 panic disorder). Patients with each AD demonstrated significantly lower EAC, including both EP and EE, than nonanxious controls. Lower EAC was also associated with higher anxiety sensitivity and higher anxiety symptom severity. Overall, gender did not moderate the anxiety-EAC effect, but the results suggested that women utilize EAC to a greater degree than men. Clinical techniques designed to improve emotional coping may be beneficial to individuals with ADs.

A PET study of tiagabine treatment implicates ventral medial prefrontal cortex in generalized social anxiety disorder.

Corticolimbic circuitry has been implicated in generalized social anxiety disorder (gSAD) by several neuroimaging symptom provocation studies. However, there are limited data regarding resting state or treatment effects on regional cerebral metabolic rate of glucose uptake (rCMRglu). Given evidence for anxiolytic effects conferred by tiagabine, a gamma-aminobutyric acid (GABA) reuptake inhibitor, the present [(18)F] fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) study sought to (1) compare resting rCMRglu between healthy control (HC) and pretreatment gSAD cohorts, (2) examine pre- to post-tiagabine treatment rCMRglu changes in gSAD, and (3) determine rCMRglu predictors of tiagabine treatment response. Fifteen unmedicated individuals with gSAD and ten HCs underwent a baseline (pretreatment) resting-state (18)FDG-PET scan. Twelve of the gSAD individuals completed an open, 6-week, flexible dose trial of tiagabine, and underwent a second (posttreatment) resting-state (18)FDG-PET scan. Compared to the HC subjects, individuals with gSAD demonstrated less pretreatment rCMRglu within the anterior cingulate cortex and ventral medial prefrontal cortex (vmPFC) at baseline. Following tiagabine treatment, vmPFC rCMRglu increased significantly in the gSAD group. Further, the magnitude of treatment response was inversely correlated with pretreatment rCMRglu within vmPFC. Taken together the present findings converge with neuroimaging findings from studies of social cognition in healthy individuals and symptom provocation in gSAD to support a role for the vmPFC in the pathophysiology of gSAD. Given the pharmacological profile of tiagabine, these findings suggest that its therapeutic effects in gSAD may be mediated by GABAergic modulation within the vmPFC.

Oxytocin levels in social anxiety disorder.

Oxytocin is a neuropeptide recently associated with social behavior in animals and humans, but the study of its function in populations with social deficits such as autism, schizophrenia, and social anxiety disorder has only recently begun. We measured plasma oxytocin in 24 patients with Generalized Social Anxiety Disorder (GSAD) and 22 healthy controls using an enzyme-linked immunosorbent assay. There were no significant differences in oxytocin level (pg/mL) between patients (M=163.0, SD=109.4) and controls (M=145.0, SD=52.9, z=0.21, P=0.8). Within the GSAD sample, however, higher social anxiety symptom severity adjusted for age and gender was associated with higher oxytocin level (R2=0.21, beta=0.014, SE=0.006, t=2.18, P=0.04). In addition, dissatisfaction with social relationships was associated with higher oxytocin levels (R2=0.18, beta=-0.20, SE=0.10, t=-2.01, P=0.05). Our data provide preliminary support for a link between social anxiety severity and plasma oxytocin. These findings may suggest a possible role for oxytocin as a facilitator of social behavior, an effect which may not be fully utilized in individuals with severe social anxiety.