Olanzapine treatment of residual positive and negative symptoms

Olanzapine has been hypothesized to have superior efficacy in patients with treatment-resistant schizophrenia. The authors examined the comparative efficacy and safety of olanzapine and haloperidol in outpatients with partially responsive schizophrenia.

Sixty-three outpatients with schizophrenia who met retrospective and prospective criteria for either residual positive or residual negative symptoms entered a 16-week double-blind, parallel-groups comparison of olanzapine and haloperidol.

There were no significant differences between the two drugs in their effect on positive or negative symptoms. There were no significant differences between the two treatment groups on measures of social and functional outcome. Olanzapine-treated patients had a significant reduction in extrapyramidal symptoms and subjective measures of stiffness and dry mouth, but the increases in systolic blood pressure and weight in olanzapine-treated patients were significantly greater than they were in haloperidol-treated patients.

Olanzapine has limited differential benefit for either positive or negative symptoms in patients with treatment-resistant schizophrenia. Although olanzapine is associated with fewer extrapyramidal symptoms, other side effects may offset this benefit.