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The placebo and nocebo effects are commonly understood as the patients’ responses to treatment in accordance with their positive or negative expectations, respectively, regarding their health. Such treatments involve substances or interventions with no known inherent effects on the studied condition, but which nonetheless may have a discernible effect on the condition’s presentation and evolution. Their influence on clinical outcomes confront practitioners with often underestimated therapeutic tools and challenges whose applicability are subject to ethical debate. Furthermore, placebos play a crucial part in our current understanding of therapeutic efficacy and in the development of novel interventions. This narrative review aims to present a brief exposition of the roles that placebo and nocebo effects play in psychiatric clinical practice and research.