Cost analysis of the treatment of schizophrenia in the UK. A simulation model comparing olanzapine, risperidone and haloperidol.

Objective: To compare the costs of 2 atypical drug therapies (olanzapine and risperidone) with one another and with a conventional antipsychotic (haloperidol) in the treatment of schizophrenia.

Design And Setting: The analysis is based on a simulation model with parameter values taken mainly from clinical trial data in patients with schizophrenia, and was conducted within a UK context.

Results: The 3 therapies are approximately cost neutral over a 5-year period (olanzapine 35,701 Pounds, risperidone 36,590 Pounds and haloperidol 36,653 Pounds). There is evidence of greater efficacy with the atypical drugs [average percentage of 5 years with Brief Psychiatric Rating Scale (BPRS) scores < 18: olanzapine 63.6%, risperidone 63.0% and haloperidol 52.2%]. The cost and efficacy differences between the 2 atypical drugs are too small to rank them in terms of cost effectiveness. Extensive sensitivity analysis does not change any of the main conclusions.

Conclusions: Given evidence of efficacy gains to the atypical drugs, these represent cost-effective treatment options. Prospective data from nontrial treatment settings would help substantiate the model findings.