Supplementary Material for: Alexithymia and Plaque Psoriasis: Preliminary Investigation in a Clinical Sample of 250 Patients

Background/Aims: Psoriasis as a dermatological disorder has complex effects on mental health and the psychological status of the patient. Many authors proposed that assessing how psoriasis affects a patient's life is better than a body surface area measurement for delineating psoriasis severity. Alexithymia is a personality dimension characterized by difficulty identifying feelings, difficulty describing feelings, and externally oriented thinking observed in many clinical conditions, especially in psychosomatic disorders. This study aimed to determine the prevalence of alexithymia in patients with plaque psoriasis compared with healthy participants, while taking into consideration demographic and clinical variables. Methods: We enrolled 250 patients with chronic plaque psoriasis, naïve to any systemic treatment, and 215 healthy individuals. The 20-item Toronto Alexithymia Scale (TAS-20) was used to assess alexithymia. Data analysis was done. Results: The mean TAS score was 53.5 (±15.3) for the patient group and 45.1 (±10.8) for controls (p < 0.0001). Compared to controls, the psoriasis group showed significant alexithymic features (32.4 vs. 9.3%), and no significant differences of alexithymia between patients with severe and mild psoriasis were observed. A significant relationship was determined between alexithymia and female gender and sensitive area involvement, such as the face, hands, and genital area. Conclusion: This study suggests that the assessment of alexithymia should be a part of the comprehensive care of patients with moderate to severe psoriasis. For this purpose, the TAS-20 is a useful and simple tool to be used in daily clinical practice.