Intensive care medicine is a relatively new speciality made possible by technological advances in artificial life support. Intensive care unit (ICU) development took its first steps at Copenhagen, with treatment using positive pressure ventilation of poliomyelitis cases. Although there are now several studies of the prevalence of depression in ICU and critically ill patients, there are relatively few in which semi-structured psychiatric assessments have been employed to measure psychiatric disorder according to strict diagnostic criteria. There are differing viewpoints about whether psychiatric conditions that are unique to, and produced by, the unusual environment of the ICU exist. This chapter discusses the impact on relatives and approaches to liaison with the ICU. The psychosocial impact of critical illness on both patient and their relatives cannot be underestimated. Patients referred from the ICU can often present with highly complex problems.