[Relations between alexithymia and anhedonia: a study in eating disordered and control subjects]

Alexithymia and anhedonia both refer to a deficit in emotion regulation. Although these 2 concepts have been conceptualized to be closely linked, very few studies aimed at examining carefully their interrelations.

Therefore, the purpose of the present study was to investigate the relationships between scores on alexithymia and anhedonia self-reports, and to assess whether the results were influenced by the presence of an emotional disorder.

The 20-item Toronto Alexithymia Scale is the self-report most frequently used to assess alexithymia. Nevertheless, the results of recent studies comparing the psychometric properties of the TAS-20 and another alexithymia self-report - the Bermond-Vorst Alexithymia Questionnaire (BVAQ) - have recommended the BVAQ over the TAS-20.

Thus, both questionnaires were included in the present study. In addition, since depression and anxiety may influence the correlations between alexithymia and anhedonia scores, we also measured depression and anxiety and these scores were used to control for their potential confounding effect in the analyses. Two groups of participants were included in this study: 46 eating disordered female patients (ED) and 198 female control subjects. All the participants filled up the Bermond-Vorst Alexithymia Questionnaire-form B (BVAQ-B), the 20-item Toronto Alexithymia Scale (TAS-20), the Chapman and Chapman Social Anhedonia Scale (SAS) and Physical Anhedonia Scale (PAS), the 13-item Beck Depression Inventory (BDI) and the Spielberger State and Trait Anxiety Inventory (STAI-Y). The analyses consisted, first, in establishing the matrix of correlations between these self-reports total scores, using Pearson's coefficients of correlation. Then, TAS-20, BVAQ-B, SAS and PAS scores were correlated, adjusting for BDI and STAI scores, using partial correlation analyses. Mean scores comparisons according to the group of participants, and to the presence/absence of alexithymia, as well as to the presence/absence of anhedonia were performed using ANCOVAs or Mann-Whitney tests.

As predicted, BDI and STAI scores were found significantly and positively correlated with alexithymia and anhedonia scores in both participant groups. After controlling for depression and anxiety scores, TAS-20 and PAS scores remained significantly correlated, but not TAS-20 and SAS scores. BVAQ-B scores remained significantly correlated with PAS and SAS scores in the control group, but only with the PAS scores in the ED group. ED patients had higher alexithymia and anhedonia scores than the controls. In total, among the alexithymic individuals, 8.9% were social anhedonics, and 31.1% had a physical anhedonia. Conversely, among the participants with a physical anhedonia, two third were alexithymics. The same proportion of participants with a social anhedonia was alexithymic (66.7%).

The results of the present study are informed about the relationships between alexithymia and anhedonia. They also stress the need to rely on several alexithymia measurements, and they further demonstrate the necessity to compare the associations between different affect regulation dimensions in normal and psychopathological disorders.