Atypical antipsychotic use for adult outpatients in New Zealand's Auckland and Northland regions.

Aim: To outline the prescribing patterns of atypical antipsychotics for adult mental health outpatients in Auckland and Northland in 2004.

Methods: All community files were reviewed retrospectively (n = 6165). Patient characteristics, diagnosis, and antipsychotic and concurrent medication were recorded and analysed.

Results: Overall, 71.3% of outpatients were prescribed an antipsychotic, of which 82.5% were atypicals: oral risperidone (30.9%), olanzapine (30.3%), quetiapine (17.1%), clozapine (26.3%), and depot risperidone (0.4%). Psychotic disorders accounted for 73.2% of outpatients on atypicals, and schizophrenia was the most common disorder overall (62.5%). Combination antipsychotic treatment occurred in 13.5% of those prescribed atypicals; 4.8% had another atypical and 8.7% had a typical co-prescribed. Clozapine was least likely to be combined with a typical antipsychotic. Those receiving combination typical and atypical antipsychotics had a greater likelihood of being prescribed an anticholinergic medication.

Conclusions: Atypical antipsychotics are the preferred treatment for outpatients with psychotic illness and are being prescribed in a manner consistent with clinical practice guidelines. Co-prescribing of antipsychotics was low, but may be causing unnecessary adverse effects and risks.