Amygdala Function and 5-HTT Gene Variants in Adolescent Anxiety and Major Depressive Disorder

Abstract

Background-Associations between a functional polymorphism in the serotonin transporter gene and amygdala activation have been found in healthy, depressed, and anxious adults. This study explored these gene-brain associations in adolescents by examining predictive effects of serotonin transporter gene variants (S and L G allele carriers vs. L A allele homozygotes) and their interaction with diagnosis (healthy vs. patients) on amygdala responses to emotional faces.

Serotonin transporter gene (5-HTT) polymorphism and major depressive disorder in patients in Bogotá, Colombia

“…The literature also shows high rates of comorbidity between major depressive disorder and anxiety disorders. Some authors recognize anxiety as an axial symptom in major depression, and have found evidence of the relationship between the polymorphism evaluated in this study and anxious symptoms, the activity of the amygdala and the anxiety response (33)(34)(35)(36). In addition, some authors have pointed out that the comorbid anxiety disorders of major depression increase implicit suicide risk (37).…”

Looking beyond the DNA sequence: the relevance of DNA methylation processes for the stress–diathesis model of depression

“…Consistent with the 5-HT alterations and various subtle neurodevelopmental alterations observed in SLC6A4 knockout mice [34][35][36], carriers of the s allele showed amygdala hyper-reactivity [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] upon exposure to emotional stimuli as well as reduced functional connectivity between the amygdala and the perigenual cingulate cortex [37]. They also showed decreased grey matter volume in limbic structures (e.g.…”

Systematic review of the neural basis of social cognition in patients with mood disorders

“…Age Neuroimaging studies conducted in children and adolescents with MDD also show heightened activation in the amygdala 56,60,74 and OFC 74 in response to emotional facial expressions (for conflicting findings, see Thomas and colleagues 42 ).…”

“…Accordingly, a number of studies reviewed here have excluded patients with comorbid psychiatric diagnoses, including anxiety disorders. 43 60 carried out subanalyses to investigate the impact of comorbidity status, finding no significant differences. Two studies 42,56 directly compared neural activity in patients with a primary diagnosis of an anxiety disorder and patients with a primary diagnosis of MDD.…”

“…Influence of facial emotion processing paradigms It should be noted that studies investigating facial emotion comprehension in patients with mood disorders employ diverse methods, such as attention bias, 49 41,42,54,56,58,60,61,63,66,80,81,83,88,89,95,196 when utilizing fMRI to uncover the neural mechanisms underlying emotion processing. During passive viewing paradigms, patients with bipolar disorder and those with MDD demonstrate hypoactivity in the DLPFC and OFC and hyperactivity in the amygdala and anterior cingulate (subgenual and pregenual), although evidence is less consistent for subcortical regions such as the amygdala and paralimbic regions.…”