Bidirectional association between psoriasis and depression: Two longitudinal follow-up studies using a national...

Few studies have investigated the bidirectional association between psoriasis and depression. The aim of our study was to identify the association between psoriasis and depression.

Data collected by the Korean Health Insurance Review and Assessment from 2002 to 2013 were used. In study I, psoriasis patients (n = 10,932) were matched 1:4 with control I group participants. In study II, depression patients (n = 60,383) were matched 1:4 with control II group participants. Matching was performed for age, sex, income, and region of residence. The stratified Cox-proportional hazard model was used to calculate the hazard ratio (HR) with crude and adjusted models.

In study I, the adjusted HR for depression was 1.13 (95% confidence interval (CI) = 1.03-1.24) in the psoriasis group compared to the control I group. In study II, the adjusted HR for depression was 1.11 (95% CI = 1.00-1.22) in the depression group compared to the control II group. In the subgroup analyses, the adjusted HRs for depression were 1.24 (95% CI = 1.00 - 1.53) in females aged < 40 years and 1.31 (95% CI = 1.04 - 1.66) in males aged ≥ 60 years. In the subgroup analyses from study II, the adjusted HRs for psoriasis were 1.56 (95% CI = 1.15 - 2.12) in males aged < 40 years and 1.35 (95% CI = 1.04 - 1.75) in males aged ≥ 60 years.

We suggest that psoriasis and depression might have a bidirectional association.