The primary aim of this study was to compare functional outcomes between patients with schizophrenia treated with olanzapine or haloperidol in Europe. The sample consisted of European patients from a large, international, double-blind, randomized clinical trial. Patients were randomized to receive either olanzapine (n = 520) or haloperidol (n = 258) for a 6-week acute phase followed by a 46-week maintenance phase for responders. Olanzapine-treated patients experienced superior improvements compared to haloperidol-treated patients on all efficacy measures assessed in both phases. A greater percentage of olanzapine-treated patients had > or = 20% improvement in the Quality of Life Scale total score during both the acute (50.0% versus 31.0%, P = 0.071) and maintenance (69.5% versus 41.7%, P = 0.006) phases compared to haloperidol-treated patients. For patients who entered the maintenance phase as outpatients, olanzapine-treated patients were significantly less likely to require subsequent hospitalization compared to haloperidol-treated patients (P = 0.001). A significantly greater percentage of the olanzapine group compared to the haloperidol group worked part-time or full-time (15.1% versus 5.3%, P = 0.018), participated in useful work > or = 75% of the time (21.0% versus 10.5%, P = 0.038), and socialized more than once a month (53.8% versus 37.9%, P = 0.004) during the maintenance phase. The findings from this study suggest that olanzapine's clinical profile leads to reduced hospitalization and improvements in work and social functioning superior to that achieved with haloperidol treatment.