Psoriasis is a complex, multifactorial chronic skin disease. As in other chronic disorders, various lifestyle factors have been associated with its morbidity. We have pointed to the significance of the patient's lifestyle practices as they relate to psoriasis outcome. Several reports in the literature suggest that exogenous and endogenous factors, including emotional stress, alcohol use, smoking, and obesity, may have deleterious effects on the increased morbidity of psoriasis. In this study, we carried out a comprehensive evaluation to assess the effects of stress, alcohol use, smoking, obesity, and exercise on the natural history of psoriasis.