Chronic plaque psoriasis has a remarkable psychological impact due to the stigmatization experienced by patients, and is associated with psychiatric comorbidities—most notably anxiety and depression—which have a much higher prevalence in psoriatic patients than in the general population and a dramatic impact on the quality of life of these patients. Furthermore, a number of personality traits have been identified in several studies to be associated with psoriasis, including alexithymia (a personality trait characterized by a reduced ability to identify and verbalize feelings), type D personality, anger, and emotional dysregulation—all of which add on to the psychological burden of psoriasis. Furthermore, a high prevalence of addictive behaviors such as high alcohol consumption and smoking has been reported in patients with the most severe forms of psoriasis. In this chapter, the personality traits and psychiatric comorbidities of patients with psoriasis will be reviewed, focusing on the subtypes of patients which are at highest risk of psychological distress and who therefore deserve the greatest attention from clinicians.