This review describes on comprehensive care for persons with Down syndrome especially in adulthood. Down syndrome is probably believed too special and therefore many clinicians seems to hesitate to attend them or scare to give wrong treatment. Quite a few psychiatrists make diagnoses of psychiatric diseases instead of behavior problems due to environmental effects and give inappropriate and/or unnecessary medication. Special care is needed on (1) muscle hypotonia, (2) characteristic mental development and developmental retardation, and (3) various complications. Complications are not too special and treatment is similar to common diseases. Persons with Down syndrome have many excellences, but maltreatment and/or environment without normalization may lead them psychiatric disorders.