What the Patient Thinks and What the Patient Does: Placebo, Nocebo, and Therapy Adherence in Ulcerative Colitis

: Patients' attitude toward therapy and adherence to treatment are central in determining the long-term outcomes of medical treatment in ulcerative colitis. A complex interplay of differing factors modulates the likelihood of persisting in or discontinuing treatment, including patients' beliefs and concerns about adverse effects of drugs, as well as the interactions with medical staff. Emotional attitude and expectancies are reflected in the so-called placebo and nocebo effects which influence patients' choices to adhere to or discontinue treatment. They represent important confounding factors in clinical trials and are amplified when the evaluation relies on patient-reported outcomes more than on objective measurements. The therapeutic gain related to placebo effects is likely also relevant in day-to-day practice, but few data are available. The aim of the present narrative review is to provide critical insight into the adherence to therapy in ulcerative colitis and its interaction with the emotional component of the effects of therapy, resulting in the placebo/nocebo effects. Understanding the mechanisms underlying patient behavior may help identify the most appropriate therapeutic approach and treatment schedule to optimize adherence and outcomes in individual patients with UC.