RT Journal Article
SR Electronic
T1 Genotype over diagnosis in amygdala responsiveness: affective processing in social anxiety disorder
JF Journal of Psychiatry and Neuroscience
JO JPN
FD Canadian Medical Association
SP 30
OP 40
VO 34
IS 1
A1 Tomas Furmark
A1 Susanne Henningsson
A1 Lieuwe Appel
A1 Fredrik Åhs
A1 Clas Linnman
A1 Anna Pissiota
A1 Vanda Faria
A1 Lars Oreland
A1 Massimo Bani
A1 Emilio Merlo Pich
A1 Elias Eriksson
A1 Mats Fredrikson
YR 2009
UL http://jpn.ca/content/34/1/30.abstract
AB 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 enrolment. 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.