Especially regarding two respects, the psychiatric expert assessment differs from the expert assessment of other medical specialties: (1) No laboratory tests or technical equipment are available for the psychiatrist except for mental disturbances due to physical impacts such as brain injuries or intoxications. The psychiatrist depends on a carefully compiled case history and a differentiated psychodiagnostic. This may lead to a wrong assessment due to a lack of objectiveness. (2) There are a lot of legal areas where only the psychiatric or psychological expert opinion is required: i.e., the question of criminal responsibility during a trial, the assessment of legal capacity and the capability to will, for decisions about the custody of children etc. This is demonstrated with some cases as an example.