Psychopathology and Alexithymia in Patients with Moderate-to-Severe Psoriasis: Development of a Novel Index with Prognostic Value

Background: Psoriasis is a chronic, relapsing, inflammatory disease with a high risk of developing mental health difficulties. Objective: The purposes of the study were to evaluate in moderate-to-severe psoriasis (a) the prevalence of depression and psychopathology, (b) the relationship between depression, psychopathology symptoms, and alexithymia, including its three dimensions, difficulty in identifying feelings (DIF), difficulty in describing feelings (DDF), and externally oriented thinking (EOT), and (c) to establish a novel index for the development of depression according to patients' psychopathological profile. Methods: In 104 patients, alexithymia was evaluated with the Toronto Alexithymia Scale (TAS-20), depression with the Beck Depression Inventory (BDI), and psychopathology with the Brief Symptom Inventory SCL-90 (SCL90). A psychopathology index that combines information from the BDI and SCL90 scales was constructed and the performance of the index with alexithymia was examined. Results: Female patients and active smokers score higher on BDI and SCL90 scales. Overweight patients tend to score arithmetically higher. The psychopathology index developed correlates significantly with age, DIF, DDF, and TAS-20. DIF, DDF, and TAS-20 are significant predictors of the psychopathology index. Patients with alexithymia/possible alexithymia are six times as likely to score higher in one of the psychopathology scales. Conclusions: Alexithymia is a significant factor in the development of psychopathology in psoriasis patients. The use of the proposed novel psychopathology index could be essential in order to identify patients with moderate-to-severe psoriasis who are more likely to experience depression and psychopathology. This could have an impact on the decision-making of psoriasis treatment and monitoring of the patient.