The relationships between health-related quality of life, illness severity, personality and psychiatric symptoms in patients with psoriasis

Introduction: Psoriasis is a chronic inflammatory skin disorder with a complex immune-mediated pathophysiology affecting between 0.91% and 8.5% of the general worldwide population and 2,1% of the Italian population (Parisi et al., 2013). The etiology of the disease is not clear, but it seems to be multifactorial, indeed both genetic factors and environmental features can contribute to begin or exacerbate the disorder (Stewart et al., 2018). Moreover, psychosomatic component may have a key role in inflammatory mechanism exacerbating by stress, indeed more than 60% of cases report stressful life events as causal or maintenance factors for the disorder. Nevertheless, stress responses are mediated by multiple influences that can compromise health when exceed personal capability and become overwhelming. Personality features can be considered as mediators in the relationship between stressors and individual response. For example, strong negative affect and social inhibition traits, put together in “Type D” personality (distressed personality), are frequently present in patients with psoriasis. Furthermore, has been found that high scores in some scales of MMPI- 2 (depression, hypochondria and hysteria) were associated to “type II” psoriasis – that is characterized by late onset and low familiarity (whereas “type I” psoriasis has an early onset and high familiarity). Various psychopathological conditions are associated with psori- asis, and they either result from or contribute to the disorder; among these we can include depression, anxiety, sleep and eating disorders, sexual dysfunctions (Verhoeven et al., 2009; Warren et al., 2011). The complex manifestation of the disorder, its psycho- logical consequences and the frequent presence of distress can reduce patients’ wellbeing, extending its negative effects in other aspects of patients’ life. Several studies have investigated the im- pact of the disorder on quality of life, reporting significative lower scores in patients with more severe lesions, psychiatric presenta- tion and/or in patients treated with conventional systemic drugs compared to biological therapy (e.g. Feldman et al., 2017). Since psoriasis is a common disorder, affecting a large part of the pop- ulation, it is important to better understand the mechanism under- lying the disorder, in an effort to reduce its impact on patients’ life. For this purpose, the study aimed at evaluating the quality of life related to the illness severity, psychiatric symptoms and personality patterns in patients with psoriasis treated with biologic or topical therapy. Notably, to date, no research has examined the relationship between quality of life and personality patterns using a clinician assessment. We consider such investigation critical for improving our understanding of the specific features of each patient and guid- ing them to the most suitable treatment. Methods: The study is based on a multi-method and multi-informant design. 50 patients, 25 assigned to a biologic therapy and 25 to a topical therapy, were evaluated with self-report measures: the Symptom Checklist-90-R (SCL-90R), that considers a wide range of psychological problems and psychopathological symptoms, both externalizing (aggression, hostility, impulsiveness) and internalizing (depression, anxiety, somatization), of psychiatric patients and non-clinical subjects; the Psoriasis Index of Quality of Life (PSORIQoL), with 25 dichotomic items evaluating the impact of psoriasis on quality of life. The items focus on fear of negative reactions from others, self-consciousness and poor self-confidence, problems with socialization, physical con- tact and intimacy, limitations on personal freedom and impaired relaxation, sleep and emotional stability. Patients’ personality and psychological functioning were also evaluated by external raters using the Shedler-Westen Assessment Procedure (SWAP-200), a clinician-report instrument, based on Q-sort methodology, with 200 items describing normal and pathological personality features. The assessment is based on the Clinical Diagnostic Interview (CDI), a semi-structured interview which explores patients’ mental and personality functioning. Finally, the severity and area of their psoriatic lesions were evaluated by dermatologists with the Psoriasis Area Severity Index (PASI) – scores (from 0 to 72) indicate body surface covered by erythema in four different body areas (head, trunk, inferior and superior limbs). Results: Significant differences between groups (biologic vs topical therapy) were found in PASI scores: patients assigned to biological therapy have shown lower levels of ill- ness severity. Nevertheless, no differences between groups were found in PSORIQoL scores. The quality of life was negatively associated with various dimensions of SCL-90R, as well as with borderline and dependent personality styles/disorders; on the contrary, it did not relate to PASI. Conclusions: Results seem to suggest that the quality of life in psoriatic patients is more influenced by personality characteristic and psychiatric symptoms rather than by the severity of psoriatic lesions