[Biosimilars and the nocebo effect].

Biosimilars have been approved for use in Germany for many years and in the meantime also in rheumatology but only a few years ago. Biosimilars, which are biotechnologically manufactured products the same as reference biologicals, have actually now achieved a substantial proportion of the market in some regions but there are still doubters among patients and physicians who fear a loss of quality even if there is no evidence for this. A part of this problem can be explained by the nocebo effect but which furthermore also has a substantial medical importance. This effect is described and explained in this article. Psychosocial and context-related factors, such as the relationship between patient and physician, previous experience with treatment and treatment expectations can either improve or impair the efficacy of treatment interventions. These phenomena are commonly known as placebo and nocebo effects. As placebo and nocebo effects can influence the development of symptoms, the frequency of undesired events and the efficacy of treatment, it is decisive to know these effects and to develop strategies for prevention in order to optimize the treatment results. Although in recent years experimental studies have achieved substantial progress in the clarification of the psychosocial and neurobiological mechanisms of placebo effects, detailed mechanisms of nocebo effects are still widely unexplored. An improved understanding of these mechanisms promises the development of user-friendly strategies for the clinical care to improve treatment results and patient satisfaction.