Protective Effects of Anti-depressants against the Subsequent Development of Psoriasis in Patients with Major Depressive Disorder: a Cohort Study.

ABSTRACT Background : Inflammation may mediate the relationship between major depressive disorder (MDD) and psoriasis. However, it is unclear whether anti-depressants can decrease the subsequent risk of psoriasis among MDD patients. This study investigated the effects of anti-depressants on the subsequent risk of psoriasis in MDD patients. Methods : This was a population-based cohort study in Taiwan. 58,454 MDD patients who had received anti-depressants and 6,034 MDD patients who did not receive anti-depressants were included. Each patient was tracked for 5 years to confirm a diagnosis of psoriasis following the index date. Cox proportional hazards models were performed to estimate the hazard ratio (HR) for psoriasis. Results : In this study, after using time-dependent Cox regression with both inverse probability of treatment weighting (IPTW) and adjustment for confounders, anti-depressant users had a significantly lower risk of psoriasis than the nonusers (IPTW-adjusted HR [aHR] = 0.69). Additionally, most types and dosages of anti-depressants tended to protect against psoriasis. Selective serotonin reuptake inhibitor use (IPTW-aHR = 0.67) and low-dose anti-depressant use (IPTW-aHR = 0.66) had significant protective effects even after IPTW and adjustment for confounders. Limitations : This study had no information about over-the-counter medications. Conclusions : This study revealed the protective effects of anti-depressants on psoriasis risk in patients with MDD. Antidepressant users had significantly lower risk of psoriasis than the nonusers. Further analyses indicated that the usage of SSRIs and low antidepressant dosage could statistically decrease risk of psoriasis.