Pain as a mediator in the temperament-alexithymia relationship in individuals suffering from rheumatoid arthritis

The study aims to establish a relationship between temperament traits, symptoms of alexithymia, and pain intensity in rheumatoid arthritis. Despite the significant progress seen in the area of RA treatment, pain, often life-long, remains the predominant symptom. This constant pain and progressing disability, as well as dependence upon other people cause RA patients to experience psychological stress that can be modified by individual patient traits. Recently, several authors have underlined the need to relate personality and temperament constructs to neurobiological processes that may underlie individual differences. It seems then that patient characteristics may play a significant role in the course of the disease.

The study was performed on a group of patients (N=317) with rheumatoid arthritis diagnosed according to the current criteria of the American-European Consensus of 2010. All patients expressed voluntary consent to participate, and the study protocol was approved by the Local Ethics Committee. This was a survey-based study. It involved the application of the adult version of the Buss and Plomin EAS Temperament Questionnaire (EAS-D), which tests 3 main temperament domains: sociability, activity, and emotionality. The pain was measured on the Visual Analogue Scale (VAS). VAS is used to measure pain intensity. The level of alexithymia was tested using the Toronto Alexithymia Scale-20. The scale consists of 20 statements and includes 3 subscales that measure difficulty in describing feelings/emotions, difficulty in identifying feelings/emotions, and operational externally oriented thinking.

The analysis revealed that alexithymia is positively correlated only with one dimension of temperament, i.e., emotionality, and with pain intensity. Moreover, high emotionality was positively correlated with pain. A simple mediation analysis revealed that pain intensity functioned as a mediator in the emotionality-alexithymia relationship.

The observed correlations indicate that RA patients with a high level of emotionality exhibit high alexithymia as they perceive pain related to the disease symptoms more intensely. The observed mediation is partial, meaning that there are also other mediating factors in this relationship.