Objective: The aim of the present study was to compare ethnic groups for antipsychotic prescribing in schizophrenia over 4.5 years. Methods: All clinical files in three mental health services caring for outpatients in Auckland, New Zealand were reviewed at two time points (T1 =31 March 2000, T2 =31 October 2004). Data were collected (patient characteristics, diagnosis, antipsychotic treatment) and analysed at each time point. Adjustments were made for age and sex in the comparisons. After the first audit, feedback was provided to all three services. Results: Differences in baseline prescribing were found between ethnic groups; rates of antipsychotic polypharmacy, second-generation antipsychotic (SGA) use, depot antipsychotic use, clozapine use and total antipsychotic dose. Overall five of the six prescribing outcome variables changed over the 4.5 years; only mean antipsychotic daily dose remained the same. Monotherapy rates increased in all ethnic groups with no difference found between them at T2 (85-86%). Similarly the prescribing variables of oral SGA use increased (83-87%), depots decreased (T2 =14-19%) and oral first-generation antipsychotics (FGAs) decreased (T2 =5-8%), all with no difference found between ethnic groups at T2. While clozapine use increased in all ethnic groups, a significant difference remained at T2; European, NZ Maori and Pacific all increased to 33-39%, but rates for Asian subjects increased only to 20%. The difference in mean daily antipsychotic dose between ethnic groups (122 mg day-1 chlorpromazine equivalent (CPZe) at T1; 86 mg day-1 CPZe at T2) reached statistical significance at both time points but overall the average dose (total mg day-1) for each group was within the usual clinical range. Adjustment for age and sex did not change the significance of any of the comparisons between ethnic groups. Conclusions: Most baseline differences in antipsychotic prescribing between ethnic groups resolved over time, with equal access for patients to recommended best practice with antipsychotic treatment in schizophrenia. Further work is required to look at differences in access to clozapine for Asian people. [ABSTRACT FROM AUTHOR]