Involuntary medication is one of the coercive measures used in psychiatry. We argue that direct extrapolation of placebo and nocebo effects of psychiatric medication in the voluntary setting to the situation of coercive treatment is probably not justified. Both placebo and nocebo effects are based upon patient expectations about the medication, but, in general, patient expectations in settings of involuntary medication tend to be less positive than in voluntary settings. As a consequence, placebo effects are likely to be diminished in coercive treatment, while nocebo effects are probably increased. This may result in an overall decreased effectiveness of medication in coercive settings. © 2011 Elsevier Ltd.