Alexithymia in healthy young men: a voxel-based morphometric study

Background: Alexithymia is a personality construct predominately associated with an impaired ability to identify and communicate emotions. Functional imaging studies showed that an altered function of the anterior cingulate cortex (ACC) may be relevant in alexithymia. In this study we investigated if the altered functional anatomy is related to structural changes (A) in the whole brain and (B) specifically in the ACC by applying a region-of-interest analysis.

Methods: 33 high- and 31 low-alexithymic right-handed young male subjects (selected by the 20-item Toronto Alexithymia Scale, TAS-20) were investigated using voxel-based morphometry (VBM) on high-resolution 3D magnetic resonance images. The group differences were analyzed by applying voxel-wise comparisons using two-sample t-tests. Moreover regression analyses with regard to the individual TAS-20 sum scores were calculated.

Results: Neither the subtraction analyses nor the correlation analyses revealed significant differences between high- and low-alexithymic subjects. Thus, according to our results, the null hypothesis of no structural difference between the groups could not be rejected.

Limitations: The findings cannot be generalized to female subjects.

Conclusions: Our results did not reveal morphological differences between high- and low-alexithymic subjects. The functional differences known from imaging studies could not be attributed to underlying anatomical changes. Thus, the personality trait of alexithymia might be associated with fewer morphological abnormalities than previously assumed.