Secondarily, we tested whether: a) joint involvement in the form of PsA independently affects brain measures; b) peripheral inflammatory marker levels in psoriasis at baseline and at imaging are associated with observed brain differences (examining neutrophils along with CRP, owing to their central role in psoriasis (Rocha-Pereira et al., 2004)); and whether c) psoriasis duration and lifetime suicidality correlate with changes in brain measures in psoriasis, based on reports that suicidality may independently drive neuroinflammation in MDD (Holmes et al., 2018). Here, CRP is linked to major depressive disorder.