Major psychiatric disorders such as major depression and schizophrenia interfere with patients' life activities and ability to function. These disorders correlate with a higher prevalence of medical and psychiatric comorbidities. To compare the admission rate of patients with major psychiatric disorders between the intensive care unit and other departments in a tertiary care center. In a retrospective study of records of 238 721 patients, data were collected from admission files and the intensive care unit computer system. The study group was 245 patients with psychiatric disorders admitted to the intensive care unit. Control groups were 9226 psychiatric patients in other hospital departments and 3032 nonpsychiatric patients in the intensive care unit. A major psychiatric disorder was diagnosed twice as often in the 3277 patients admitted to the intensive care unit as in patients admitted to other departments (7.5% vs 3.8%, P < .001). The study group had fewer male patients than did the nonpsychiatric intensive care unit group (52% vs 66%, P < .001); the age distribution was similar. Patients with a psychiatric disorder required longer stays than other intensive care unit patients. However, their mortality rate was significantly lower (8.57% vs 17.1%, P = .001). A direct correlation between the admission and a psychiatric condition was found in one-third of admissions in the study group. Psychiatric patients' admission rate to the intensive care unit was significantly higher than their admission rate to other departments. Their intensive care unit stays were also longer, which may increase resource use.