Ten years after the institution of a Day Hospital in Rome, the authors make an assessment of treatment results achieved for 70 patients admitted for the first time in 1986 and assessed after five years. Literary studies emphasizing Day Hospital effectiveness are reviewed; then the authors describe the setting in which this research was carried out. The primary aim was: to evaluate the efficacy of this unit to satisfy its users' needs, to permit their reentry into the community and to prevent their relapses and rehospitalizations.