Research paperEffects of subclinical depression, anxiety and somatization on brain structure in healthy subjects

•Subclinical depression and anxiety might be associated with brain structure.•We studied 177 healthy controls with VBM and self-assessment of minor symptoms.•Depression, anxiety and somatoform symptoms show associations with brain structure.•Our findings support a biological continuum of depression and anxiety.

BackgroundDimensional approaches in highly prevalent psychiatric disorders like depression or anxiety could lead to a better understanding of pathogenesis and advantages in early detection and prevention. In an effort to better understand associations of brain structural variation across the depression/anxiety spectra, we investigated minor subclinical symptoms in a non-clinical healthy population.MethodsWe studied 177 healthy subjects from the community, who underwent high-resolution T1-weighted 3T MRI and completed the symptom-checklist-90 (SCL-90-R). Using voxel-based morphometry (VBM) analysis with CAT12 software, we correlated SCL-90-R-subscales for depression, anxiety, and somatization with gray matter across the brain.ResultsSignificant positive gray matter correlations emerged across all three scales in different areas: the depression subscale correlated positively with gray matter in the Rolandic operculum, superior temporal gyrus (left) and postcentral gyrus (bilateral), the anxiety subscale correlated positively with middle temporal gyrus, Rolandic operculum, middle cingular gyrus and precuneus bilaterally, and the somatization subscale with left inferior prefrontal cortex. Somatization also showed negative correlations with cerebellar vermis and right supplementary motor area.LimitationsOur study is limited to VBM and does not include surface-based measures. It also only contains subjects with very small psychological distress by partly overlapping symptoms.ConclusionOur findings are consistent with a non-linear relationship between symptom severity and cortical volume in several brain areas involved in both emotion regulation as well as altered in clinically manifest depressive/anxiety disorders.