OBJECTIVE: To examine recent pharmacologic treatment patterns for hospitalized schizophrenia patients. METHODS: Premier's PerspectiveTM database, the largest U.S. hospital drug utilization database, was used to identify hospitalized schizophrenia patients discharged between January 1999 and September 2001. Treatment regimens for five classes of psychotropics were analyzed. Regressions examined relationships between polypharmacy patterns and diagnoses, illness severity, and patient and institution characteristics. RESULTS: Of 42,233 patients (55% male, mean age 42 years), 94.9% received antipsychotics; 74.4% atypicals, most commonly olanzapine (46.5%). Mood stabilizers were used by 40.9% of patients, antidepressants by 47.6%, anxiolytics by 66.8%, and hypnotics by 23.4%. Only 7.9% of patients received monotherapy. On average, patients received 3.67 psychotropics; 74.2% received 3 and 27.4% received 5 psychotropics. Most common regimens were antipsychotic and anxiolytic combinations (13.6%); this combination plus either antidepressants (12.2%), mood-stabilizers (10.5%), or both (9.9%); and antipsychotics alone (9.6%). Greater severity, female, paranoid or schizoaffective diagnoses, non-teaching and for-profit hospitals were associated with increased polypharmacy use. Patients in public programs (Medicaid/Medicare) received less atypical antipsychotics but more polypharmacy compared to those in managed care and commercial programs. Atypical antipsychotic use increased and lithium use decreased from 1999-2001. CONCLUSIONS: Polypharmacy is common among hospitalized schizophrenia patients. Patient and institution characteristics influenced treatment.