Scientific clinical research in psychiatry has to fulfil the same ethical and legal requirements as research in somatic medicine: studies have to be valid; studied subjects have to give informed consent; and studies have to be approved by an investigational review board. With respect to the criterion of validity, there is no motive to give research in psychiatry a special place: it has to fulfil the same methodological requirements of science. Although some psychiatric patients can not express their free will, most psychiatric patients are capable to judge their participation in scientific clinical research and to give informed consent as well as most patients with somatic diseases. Placebocontrolled studies in psychiatry are ethically permissible, at least short lasting studies involving not too severely ill patients. In contrast, longer lasting placebo-controlled studies, e.g. the maitenance treatment of bipolar disorder, are not or less permissible, while from a practical point of view it is almost impossible to perform such studies.