In the controlled and uncontrolled studies, community care as alternatives to in-patient care yielded similar or better outcomes. The aim of this study is to compare the direct cost of in-patient and home based care of acute mental illness from the health care provider's perspective.

82 patients exclusively treated as in-patient and 80 patients exclusively treated at home in 2008 on account of acute mental illness, in the psychiatric department of an Irish general hospital were suitable for stratified randomisation in each group. 32 patients were selected from each group. Micro-costing technique was used to retrospectively estimate from the clinical record, the direct costs of treatment for each patient (n=64).

The average direct cost per patient treated in the hospital was €5,579 (range, €1,668 - €24,048, 95% confidence interval (CI) of €3808 to €7350), compared to €3,977 (range, €779 - €10,355, 95% CI of €3034 to €4921) for each patient treated at home. The average daily in-patient admission cost was €343 (95% CI of €332 to €354), compared to €147 (95% CI of €142 to €152) per day for each patient treated at home.

Home based care of adult patients presenting with acute mental illness, that could have been admitted in the absence of a home based treatment unit incurred lower daily costs to the health care provider compared to in-patient care (Mann-Whitney U test, z=6.876, p=0.000). This underscores the need for more researches to further develop Home based models of acute mental illness care.