Distinct associations of insula and cingulate volume with the cognitive and affective dimensions of alexithymia Katharina Sophia Goerlich-Dobre a,b,n , Lori Bruce c,d , Sander Martens a , André Aleman a,e , Christine I. Hooker d a Neuroimaging Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands b Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen 52074, Germany c Interdisciplinary Department for Bioethics, Yale University, New Haven, CT, United States d Department of Psychology, Harvard University, Cambridge, MA, United States e Department of Psychology, University of Groningen, Groningen, The Netherlands article info Article history: Received 22 March 2013 Received in revised form 16 November 2013 Accepted 5 December 2013 Available online 13 December 2013 Keywords: Alexithymia dimensions Cognitive Affective Voxel-based morphometry Insula Cingulate cortex abstract Alexithymia (“no words for feelings”) is a major risk factor for psychosomatic and psychiatric conditions characterized by affect dysregulation. The alexithymia personality construct comprises an affective dimension, the level of subjective emotional experience (emotionalizing and fantasizing), and a cognitive dimension, referring to the cognitive control of emotions (identifying, analyzing, and verbalizing feelings). These two dimensions may differentially put individuals at risk for psychopathology, but their specific neural bases have rarely been investigated. Therefore, the aim of the present study was to find out whether the two alexithymia dimensions are associated with discriminable neural correlates. By means of voxel- based morphometry (VBM), differences in gray matter volumes were compared between 20 (10 male) high-scorers and 20 (9 male) low-scorers on the Toronto Alexithymia Scale (TAS-20), reflecting the cognitive alexithymia dimension. In a subset of 32 subjects, the impact of the affective alexithymia dimension was tested in addition, as assessed with the affective subscale of the Bermond–Vorst Alexithymia Questionnaire (BVAQ). Analysis 1 (cognitive alexithymia dimension) revealed significantly larger gray matter volumes in the right posterior insula in high-scorers compared to low-scorers on the TAS-20. Analysis 2 (affective alexithymia dimension) revealed that the affective alexithymia dimension, specifically the emotionalizing factor indicative of low emotional reactivity, was associated with larger gray matter volumes of the right cingulate cortex. These results suggest that the two alexithymia dimensions are associated with distinct structural correlates. & 2013 Elsevier Ltd. All rights reserved. 1. Introduction With a prevalence rate of ten percent in the general popula- tion, alexithymia (“no words for feelings”) is a major risk factor for a range of medical and psychiatric disorders (Taylor, Bagby, & Parker, 1997), including somatoform (Waller & Scheidt, 2004) and panic disorders (Parker, Taylor, & Bagby, 1993). In general, men seem to exhibit higher levels of alexithymia than women, though gender differences are small (Levant, Hall, Williams, & Hasan, 2009). Although alexithymia has long been thought of as a unidimensional construct, it is now acknowledged that it com- prises two dimensions, an affective and a cognitive one (Vorst & Bermond, 2001). The cognitive dimension refers to the proces- sing of emotions at the cognitive level and comprises low abilities to identify, analyze, and verbalize one's feelings. These three cognitive alexithymia facets are traditionally assessed with the TAS-20 Toronto Alexithymia Scale (Bagby, Parker, & Taylor, 1994a; Bagby, Taylor, & Parker, 1994b), which comprises the three subscales ‘difficulty identifying feelings', ‘difficulty describ- ing feelings', and ‘externally oriented thinking'. For the TAS-20, a clinical cut-off score has been established that classifies a score equal to or higher than 61 as a clinically relevant alexithymia score (Taylor et al., 1997). The affective alexithymia dimension refers to the level of subjective emotional experience and comprises low degrees of emotional arousal in response to emotion-inducing events (emotionalizing factor), and reduced imaginative capabilities (fantasizing factor). While these affective factors are not part of the TAS-20, they can be assessed by means of the Bermond–Vorst Alexithymia Questionnaire (BVAQ, Vorst & Bermond, 2001). Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/neuropsychologia Neuropsychologia 0028-3932/$ - see front matter & 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.neuropsychologia.2013.12.006 n Corresponding author at: RWTH Aachen University Hospital, Department of Psychiatry, Psychotherapy, and Psychosomatics, Pauwelsstrasse 30, 52074 Aachen, Germany. Tel.: þ49 241 80 88334. E-mail addresses: kgoerlich@ukaachen.de, katharina.goerlich@gmail.com (K.S. Goerlich-Dobre). Neuropsychologia 53 (2014) 284–292