Patterns of sub-optimal antipsychotic use and misuse in Australia: What can routinely collected data tell us?

INTRODUCTION: There are increasing concerns about harms related to sub-optimal antipsychotic use. Here we describe recent population-based trends in antipsychotic use and harms in Australia and identify population groups exhibiting patterns of use likely to contribute to these harms.

METHODS: Using population-based data from the Australian Pharmaceutical Benefits Scheme (2015-2020); poisoning calls to New South Wales (NSW) Poisons Information Centre (2015-2020); and poisoning deaths in all coronial records (2005-2018) in Australia, we measured trends in the prevalence of antipsychotic use and related deaths and poisonings. We applied latent class analyses to identify patterns of antipsychotic use that may contribute to harms.

RESULTS: Quetiapine and olanzapine had the highest prevalence of use between 2015 and 2020. Noteworthy trends included increases of 9.1% and 30.8% in quetiapine use and poisonings, while olanzapine use decreased by 4.5% but poisonings increased by 32.7%. Quetiapine and olanzapine poisonings and related deaths had the highest rates of co-ingestion of opioids, benzodiazepines and pregabalin compared to other antipsychotics. We identified six distinct population groups using antipsychotics including i) ongoing high-dose use with sedatives (8%), ii) ongoing use (42%), iii) ongoing use with analgesics and sedatives (11%), iv) long-term low-dose use (9%), v) sporadic use (20%), and vi) sporadic use with analgesics (10%).

CONCLUSIONS: Ongoing potentially sub-optimal antipsychotic use and associated harms highlight the need to monitor such patterns of use, for example through prescription monitoring systems.