| 1. |
- Engman, Jonas, et al.
(författare)
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Neural Correlates of Anxiety States in Patients with Social Anxiety Disorder
- 2011
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Ingår i: Biological Psychiatry. - 0006-3223 .- 1873-2402. ; 69, s. 70S-70S
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: In social anxiety disorder (SAD), the fear of being negatively evaluated by others can restrict individual everyday life, due to the anxiety caused by social interactions. How this anxiety is processed in the brain is only partly understood. We aimed to examine the correlations between subjective anxiety states and brain activity in a large sample of SAD patients, during an anxiety-provoking task.Methods: Data were merged from three randomized clinical PET-trials investigating regional cerebral blood flow (rCBF) during a public speaking task pre- and post treatment (SSRI n = 35, placebo n = 37). All participants met diagnostical criteria for SAD. rCBF was assessed with [15O]-labeled water and state anxiety was measured using the Spielberger state anxiety scale (STAI-S). These measures where then correlated using a covariate of interest approach in Statistical Parametric Mapping (SPM2).Results: rCBF and STAI-S scores correlated positively in the left parahippocampal gyrus and amygdala, as well as in the right premotor cortex (area 6). Negative correlations were observed in the left superior frontal gyrus, thalamus, and the right parahippocampal gyrus. Negative correlations were also found bilaterally in the cerebellum.Conclusions: The correlations between clinical anxiety states and brain activity were noted in areas previously demonstrated to be involved in emotional regulation and motor preparedness.
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| 2. |
- Faria, Vanda, et al.
(författare)
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Amygdala-frontal couplings characterizing SSRI and placebo response in social anxiety disorder
- 2014
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Ingår i: International Journal of Neuropsychopharmacology. - : Oxford University Press. - 1461-1457 .- 1469-5111. ; 17:8, s. 1149-57
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: In patients with social anxiety disorder (SAD) it has been reported that selective serotonin reuptake inhibitors (SSRIs) and placebo induce anxiolytic effects by attenuating neural activity in overlapping amygdala subregions, i.e. left basolateral and right ventrolateral amygdala. However, it is not known whether these treatments inhibit amygdala subregions via similar or distinct brain pathways. As anxiolytic treatments may alter amygdala-frontal couplings we investigated differences and similarities in amygdala-frontal functional co-activation patterns between responders and nonresponders to SSRIs and placebo in patients with SAD. Positron emission tomography (PET) with oxygen-15-labeled water was used to measure anxiety-related regional cerebral blood flow in 72 patients with SAD before and after 6-8 wk of treatment under double-blind conditions. Functional couplings were evaluated with a seed region approach using voxel values from the left basolateral and right ventrolateral amygdala. Responders and nonresponders to SSRIs and placebo showed different treatment-induced co-activations between the left amygdala and the dorsolateral prefrontal cortex (dlPFC) as well as the rostral anterior cingulate cortex (ACC). Conjunction analysis suggested shared anxiolysis-dependent inverse co-activations in SSRI and placebo responders between the left amygdala-dlPFC and left amygdala-rostral ACC, and a shared positive co-activation between left amygdala-dorsal ACC. We demonstrate that amygdala-frontal co-activation patterns differentiate effective from ineffective anxiolytic treatments and that SSRI and placebo responders share overlapping neuromodulatory paths that may underlie improved emotion regulation and reduced expression of anxiety.TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00343707.
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| 3. |
- Faria, Vanda, et al.
(författare)
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Amygdala Subregions Tied to SSRI and Placebo Response in Patients with Social Anxiety Disorder
- 2012
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Ingår i: Neuropsychopharmacology. - : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 37:10, s. 2222-2232
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Tidskriftsartikel (refereegranskat)abstract
- The amygdala is a key structure in the pathophysiology of anxiety disorders, and a putative target for anxiolytic treatments, Selective serotonin reuptake inhibitors (SSRIs) and placebo seem to induce anxiolytic effects by attenuating amygdala responsiveness. However, conflicting amygdala findings have also been reported. Moreover, the neural profile of responders and nonresponders is insufficiently characterized and it remains unknown whether SSRIs and placebo engage common or distinct amygdala subregions or different modulatory cortical areas. We examined similarities and differences in the neural response to SSRIs and placebo in patients with social anxiety disorder (SAD). Positron emission tomography (PET) with oxygen-15-labeled water was used to assess regional cerebral blood flow (rCBF) in 72 patients with SAD during an anxiogenic public speaking task, before and after 6-8 weeks of treatment under double-blind conditions. Response rate was determined by the Clinical Global Impression-Improvement scale. Conjunction analysis revealed a common rCBF-attenuation from pre- to post-treatment in responders to SSRIs and placebo in the left basomedial/basolateral and right ventrolateral amygdala. This rCBF pattern con-elated with behavioral measures of reduced anxiety and differentiated responders from nonresponders. However, nonanxiolytic treatment effects were also observed in the amygdala. All subgroups, including nonresponders, showed deactivation of the left lateral part of the amygdala. No rCBF differences were found between SSRI responders and placebo responders. This study provides new insights into the brain dynamics underlying anxiety relief by demonstrating common amygdala targets for pharmacologically and psychologically induced anxiety reduction, and by showing that the amygdala is functionally heterogeneous in anxiolysis.
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| 4. |
- Faria, Vanda, et al.
(författare)
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Differences in Amygdala Responsivity Between Responders and Nonresponders to SSRIs in Patients with Social Anxiety Disorder
- 2011
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Ingår i: Biol. Psychiatry 69, 70S-71S.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: Selective serotonin reuptake inhibitors (SSRIs) are commonly accepted as the first line pharmacological therapy for anxiety disorders and depression. However, there is a high percentage of patients that fail to achieve satisfactory response with SSRI treatments. The neural mechanisms underlying effective and ineffective outcome with SSRIs are not well characterized. The amygdala has dense serotonergic innervation, and studies have suggested the amygdala to be a crucial brain target for SSRI treatment. This study aimed at investigating differences in amygdala responsivity between responders and nonresponders to SSRI treatments in patients with social anxiety disorder (SAD).Methods: Stress-related regional cerebral blood flow (rCBF) was measured in SAD patients (n=35) with 15O-water positron emission tomography (PET) during public speaking before and after 6-8 weeks of treatment with citalopram or paroxetine. Response rate was determined by the Clinical Global Impression-Improvement scale.Results: Within-group comparisons revealed reduced rCBF response bilaterally in the amygdala in responders (n=20) as well as in nonresponders (n=15). Between-group contrasts revealed a greater amygdala attenuation in responders (>nonresponders) in the left basolateral/basomedial (x-16, y-6, z-14, Z=1.66, Puncorr=0.024) and right ventrolateral subregions (x26, y-4, z-26, Z=2.12, Puncorr=0.009). However, greater rCBF attenuation in nonresponders (> responders) was observed in the left lateral amygdala (x-28, y-6, z-14, Z=2.38, Puncorr=0.005).Conclusions: Lowered amygdala responsivity does not seem to be exclusively related to clinical improvement in anxiety patients. In accordance with animal literature, our data suggest that amygdala subregions are functionally heterogeneous with regards to anxiolysis.
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| 5. |
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| 6. |
- Frick, Andreas, et al.
(författare)
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Reduced serotonin synthesis and regional cerebral blood flow after anxiolytic treatment of social anxiety disorder
- 2016
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Ingår i: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 26:11, s. 1775-1783
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Social anxiety disorder (SAD) is associated with increased fear-related neural activity in the amygdala and we recently found enhanced serotonin synthesis rate in the same region. Anxiolytic agents like selective serotonin re-uptake inhibitors (SSRIs) and neurokinin-1 receptor (NK1R) antagonists reduce amygdala activity and may attenuate serotonin formation according to animal studies. Here, we examined the effects of SSRI pharmacotherapy, NK1R antagonism, and placebo on serotonin synthesis rate in relation to neural activity, measured as regional cerebral blood flow (rCBF), and symptom improvement in SAD. Eighteen SAD patients were randomized to receive daily double-blind treatment for six weeks either with the SSRI citalopram (n=6; 40 mg), the NK1R antagonist GR205171 (n=6; 5 mg; 4 weeks following 2 weeks of placebo), or placebo (n=6). Serotonin synthesis rate at rest and rCBF during stressful public speaking were assessed, before and after treatment, using positron emission tomography with the tracers [11C]5-hydroxytryptophan and [15O]water respectively. The Liebowitz Social Anxiety Scale (LSAS-SR) indexed symptom severity. All groups exhibited attenuated amygdala serotonin synthesis rate after treatment, which was associated with reduced amygdala rCBF during public speaking and accompanied by symptom improvement. These results are consistent with the notion that serotonin in the amygdala exerts an anxiogenic influence and, conversely, that anxiolysis is achieved through decreased serotonin formation in the amygdala.
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| 7. |
- Furmark, Tomas, et al.
(författare)
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A link between serotonin-related gene polymorphisms, amygdala activity, and placebo-induced relief from social anxiety
- 2008
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 28:49, s. 13066-74
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Tidskriftsartikel (refereegranskat)abstract
- Placebo may yield beneficial effects that are indistinguishable from those of active medication, but the factors underlying proneness to respond to placebo are widely unknown. Here, we used functional neuroimaging to examine neural correlates of anxiety reduction resulting from sustained placebo treatment under randomized double-blind conditions, in patients with social anxiety disorder. Brain activity was assessed during a stressful public speaking task by means of positron emission tomography before and after an 8 week treatment period. Patients were genotyped with respect to the serotonin transporter-linked polymorphic region (5-HTTLPR) and the G-703T polymorphism in the tryptophan hydroxylase-2 (TPH2) gene promoter. Results showed that placebo response was accompanied by reduced stress-related activity in the amygdala, a brain region crucial for emotional processing. However, attenuated amygdala activity was demonstrable only in subjects who were homozygous for the long allele of the 5-HTTLPR or the G variant of the TPH2 G-703T polymorphism, and not in carriers of short or T alleles. Moreover, the TPH2 polymorphism was a significant predictor of clinical placebo response, homozygosity for the G allele being associated with greater improvement in anxiety symptoms. Path analysis supported that the genetic effect on symptomatic improvement with placebo is mediated by its effect on amygdala activity. Hence, our study shows, for the first time, evidence of a link between genetically controlled serotonergic modulation of amygdala activity and placebo-induced anxiety relief.
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| 8. |
- Furmark, Tomas, et al.
(författare)
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Cerebral blood flow changes after treatment of social phobia with the neurokinin-1 antagonist GR205171, citalopram, or placebo.
- 2005
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Ingår i: Biol Psychiatry. - : Elsevier. - 0006-3223 .- 1873-2402. ; 58:2, s. 132-42
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Evidence is accumulating that pharmacological blockade of the substance P preferring neurokinin-1 (NK1) receptor reduces anxiety. This study compared the effects of an NK1 receptor antagonist, citalopram, and placebo on brain activity and anxiety symptoms in social phobia. METHODS: Thirty-six patients diagnosed with social phobia were treated for 6 weeks with the NK1 antagonist GR205171 (5 mg), citalopram (40 mg), or matching placebo under randomized double-blind conditions. GR205171 was administered for 4 weeks preceded by 2 weeks of placebo. Before and after treatment, regional cerebral blood flow (rCBF) during a stressful public speaking task was assessed using oxygen-15 positron emission tomography. Response rate was determined by the Clinical Global Impression Improvement Scale. RESULTS: Patients improved to a larger extent with the NK1 antagonist (41.7% responders) and citalopram (50% responders), compared with placebo (8.3% responders). Within- and between-group comparisons showed that symptom improvement was paralleled by a significantly reduced rCBF response to public speaking in the rhinal cortex, amygdala, and parahippocampal-hippocampal regions. The rCBF pattern was corroborated in follow-up analyses of responders and subjects showing large state anxiety reduction. CONCLUSIONS: Short-term administration of GR205171 and citalopram alleviated social anxiety. Neurokinin-1 antagonists may act like serotonin reuptake inhibitors by attenuating neural activity in a medial temporal lobe network.
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| 9. |
- Furmark, Tomas, et al.
(författare)
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Genotype over-diagnosis in amygdala responsiveness: affective processing in social anxiety disorder.
- 2009
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Ingår i: Journal of psychiatry & neuroscience : JPN. - : Canadian Medical Association. - 1488-2434 .- 1180-4882. ; 34:1, s. 30-40
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although the amygdala is thought to be a crucial brain region for negative affect, neuroimaging studies do not always show enhanced amygdala response to aversive stimuli in patients with anxiety disorders. Serotonin (5-HT)-related genotypes may contribute to interindividual variability in amygdala responsiveness. The short (s) allele of the 5-HT transporter linked polymorphic region (5-HTTLPR) and the T variant of the G-703T polymorphism in the tryptophan hydroxylase-2 (TPH2) gene have previously been associated with amygdala hyperresponsivity to negative faces in healthy controls. We investigated the influence of these polymorphisms on amygdala responsiveness to angry faces in patients with social anxiety disorder (SAD) compared with healthy controls. METHODS: We used positron emission tomography with oxygen 15-labelled water to assess regional cerebral blood flow in 34 patients with SAD and 18 controls who viewed photographs of angry and neutral faces presented in counterbalanced order. We genotyped all participants with respect to the 5-HTTLPR and TPH2 polymorphisms. RESULTS: Patients with SAD and controls had increased left amygdala activation in response to angry compared with neutral faces. Genotype but not diagnosis explained a significant portion of the variance in amygdala responsiveness, the response being more pronounced in carriers of s and/or T alleles. LIMITATIONS: Our analyses were limited owing to the small sample and the fact that we were unable to match participants on genotype before enrollment. In addition, other imaging techniques not used in our study may have revealed additional effects of emotional stimuli. CONCLUSION: Amygdala responsiveness to angry faces was more strongly related to serotonergic polymorphisms than to diagnosis of SAD. Emotion activation studies comparing amygdala excitability in patient and control groups could benefit from taking variation in 5-HT-related genes into account.
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