Can SSRI/SNRI antidepressants decrease the 'cytokine storm' in the course of COVID-19 pneumonia?

Background: Lots of research has been conducted to fight COVID-19 since the outbreak of the pandemic in 2020. The role of 'cytokine storm' in the pathogenesis of COVID-19 pneumonia is well known. Relationship between interleukins and depression is still subject matter of the research, but a correlation between interleukin-6 and depressive disorders is proven by now. The aim of this study is to verify differences among interleukin-6 blood levels of inpatients treated with SSRI and/or SNRI before and during hospitalization and of inpatients not treated with these drugs. Methods: This is an observational study performed during the first wave of SARS Cov-2 pandemic in Italy for three months. The hospitalized patients of Internal Medicine wards and Infectious and Tropical Diseases ward of Azienda Ospedaliero-Universitaria Careggi of Florence for COVID-19 pneumonia have been divided into two subgroups (treated / not treated with antidepressants). Patients admitted to Intensive Care Unit previously have been excluded. Each patient has been evaluated concerning demographic, clinical and therapeutic features. The first dosage of interleukin-6 detected during hospitalization has been noticed. Results: 8,5% (n=34 patients) of the entire sample (n=402) had been treated with an antidepressant of the two considered categories before admission until discharge from hospital. Significant lower levels of interleukin-6 of recovered patients of the treated subgroup have been highlighted as compared to recovered patients of not-treated subgroup (12,1 vs 25,4 p<0,001). These results have been pointed out in spite of higher mean age and more serious comorbidities of the treated subgroup. Nevertheless the incidence of severe Acute Respiratory Distress Syndrome is significantly lower in the subgroup of patients with antidepressant treatment (20,6% vs 43,2% p<0,02) as well as endotracheal intubation employment (0,0% vs 11,7% p<0,04). The rate of deceased patients of treated-subgroup is not significant lower than the rate of not-treated subgroup (23,5% vs 26,4% p=0,13). Conclusions: During COVID-19 pneumonia, the production of interleukin-6 seems to be modulated in presence of antidepressant therapy. Further proofs and broader surveys are necessary.