Psychological Stress and Salivary Cortisol Levels in Patients with Plaque Psoriasis

Psychological stress has long been recognized as a trigger for plaque psoriasis, and pre- liminary evidence suggests that psoriasis could be associated with alterations in the hypothalamic- pituitary-adrenal (HPA) axis, resulting in impaired cortisol response to stress. This study aimed to investigate psychological stress, anxiety, depression and salivary cortisol in psoriatic patients. A cross sectional study involving 126 adult patients with plaque psoriasis and 116 adult healthy controls was conducted. Demographic, clinical data, Perceived Stress Scale (PSS) and Hospital Anxiety and Depression Scale (HADS) were collected. Cases and controls were asked whether they felt stressed in the last month, whilst psoriatic patients were also interrogated whether they found that psoriasis could have been worsened by stress. Moreover, 54 randomly selected subjects (27 psoriasis patients and 27 controls) underwent salivary cortisol testing at 8 am. PSS, HADS depression and anxiety subscales were significantly higher in psoriatic patients than in controls (17.2 ± 0.6 vs. 15.1 ± 0.8 p = 0.0289), (9.5 ± 0.3 vs. 6.2 ± 0.3 p < 0.001) and (8.2 ± 0.4 vs. 4.2 ± 0.3 p < 0.001), respectively. A higher rate of psoriatic patients reported feeling stress over the last month (45% vs. 19%, p < 0.001), and stress was considered a potential trigger for psoriasis flare-ups in 69% of cases. Psoriasis was strongly associated with higher PSS and HADS scores independently of sex, body mass index, dia- betes, hypertension, dyslipidemia, and occupational status. Salivary cortisol was significantly lower in psoriatic patients compared to controls (9.6 ± 0.5 vs. 14.0 ± 1.1 nmol/L, p < 0.001). In conclusion, psoriasis was associated with higher psychological stress, anxiety and depressive symptoms, and with impaired cortisol response to stress.