Role of Serotonin and Dopamine in Psoriasis: A Case-Control Study

BACKGROUND: Psoriasis is a chronic inflammatory disease mediated by the immune system with increased proliferation of keratinocytes. The exact cause is unknown but as a multifactor, such as infection, trauma and psychological stress have been thought to play a role in its pathophysiology. Dopamine and serotonin are believed to have a strong role in stress conditions and also directly play a role in psoriasis. AIM: This study aimed to evaluate the role of dopamine, serotonin, and psychological stress in psoriasis. METHODS: This study used a case-control design involving 30 patients with psoriasis (as a case group) and 30 healthy controls in the Dermatology and Venereology Polyclinic of Sanglah General Hospital Denpasar during the period December 2016 to February 2017. All samples were taken for venous blood examination serum dopamine and serotonin and analysed using the ELISA method. Statistical analysis using an independent t-test, partial correlation, receiver operator characteristic (ROC) curve, and logistic regression model. RESULT: There were significant differences in serotonin, dopamine, and stress index levels between groups with psoriasis and non-psoriasis (102.68 ± 25.44 Vs. 154.17 ± 20.90; p < 0.001), (437.13 ± 164.83 Vs. 138.11 ± 89.51; p < 0.001), and (138.5 ± 27.80 Vs. 92.55 ± 42.97; p < 0.001). Significant negative correlation was found between serotonin level and stress index (r = -0.366; p = 0.016) and between serotonin and dopamine (r = -0.634; p < 0.001) but a positive correlation was found between dopamine and stress index (r = 0.459; p = 0.042). Serotonin and dopamine showed that it could be used as a biochemical predictive model for psoriasis (AUC > 0.7). Multivariable risk analysis model high serum dopamine was the most important risk factor for the occurrence of psoriasis (adjusted OR: 7.8; 95% CI: 3.45-15.57; p = 0.024) CONCLUSION: Serotonin and dopamine have a significant role in the pathophysiology of the occurrence of psoriasis, and psychological stress can affect psoriasis through its influence on serotonin and dopamine.