TNF and psoriasis: Clinical trials have already demonstrated the antidepressant benefits of several immunotherapies, such as etanercept (TNF-alpha antagonist used to treat a range of autoimmune conditions, including psoriasis and arthritis), infliximab (monoclonal antibody against TNF-alpha also used for the treatment of autoimmune diseases), and celecoxib [cyclooxygenase (COX)-2 inhibitor used to treat pain and arthritis] (82, 83).