Autor:innen:
L. Sindermann (Bonn, DE)
J. Böhnlein (Münster, DE)
R. Lennings (Münster, DE)
K. Roesmann (Münster, DE)
U. Lueken (Berlin, DE)
F. Seeger (Würzburg, DE)
H. Schwarzmeier (Heidelberg, DE)
T. Kircher (Marburg, DE)
I. Nenadic (Marburg, DE)
U. Dannlowski (Münster, DE)
E. Leehr (Münster, DE)
Background: Major depressive disorder (MDD) and anxiety disorders (AD) share common symptoms and often co-occur. Further, shared symptoms are associated with an aberrant bottom-up stimulus-driven processing (negativity bias in MDD; automatic fear reaction in AD). Those symptoms are linked to regions orchestrating fast defensive reactions (amygdala, thalamus). Investigating structural commonalities and differences in those regions in MDD and AD is of special interest because the neural underpinnings of psychopathology in both disorders are not fully understood. Methods: We applied voxel-based morphometry in n= 88 patients with MDD, n= 89 patients with specific phobia as a model disorder for pathological defensive reactions (SP; animal sub-type spider phobia), and n= 87 healthy controls. All participants come from larger cohort studies (MACS: Kircher et al., 2019; C09: Schwarzmeier et al., 2020). The amygdala and thalamus were analysed combined as regions of interest (ROI), accompanied by exploratory whole-brain (WB) analyses. Results: ROI analysis revealed reduced bilateral thalamic volume in SP compared to MDD (right: xyz, 22, -21, 10, t(173)= 4.73, k= 105, pFWE= .001, d= .71; left: xyz, -22, -22, 6, t(173)= 4.21, k= 28, pFWE= .006, d= .63) and HC (left: xyz, -22, -20, 6, t(172)= 3.82, k= 11, pFWE= .023, d= .58). No difference regarding thalamic volume between MDD and HC was found (pFWE> .05). On WB level, group comparisons showed an increased parahippocampal volume in SP compared to MDD and HC, and a reduced superior frontal gyrus volume in MDD compared to HC. Conclusions: Thalamic volume seems to distinguish between individuals with SP from individuals with MDD or HC. It might be that the reduced thalamus volume represents a potential biomarker for SP sub-type spider phobia. Generalizability to phobic AD or AD in general remains unclear. This finding might indicate the relevance of the thalamus in the psychopathology of spider phobia.