Psychotropic medication use in Australia, 2007 to 2015: Changes in annual incidence, prevalence and treatment exposure

Objective: To examine changes in annual patterns of psychotropic medication use in Australia from 2007 to 2015. Methods: We used a 10% sample of individual-level nationwide dispensing claims for concessional beneficiaries dispensed psychotropic medications (stratified by class, subclass) to investigate annual trends and changes in the incidence and prevalence of use, median annual duration of exposure, proportion of people with single psychotropic dispensing and median defined daily doses per person dispensed each medicine per year. Results: Over the study period, there was a 26.1% decrease in the incidence and a 2.6% increase in the prevalence of all psychotropic medicine use. We observed a decrease in the annual incidence and prevalence of antidepressants (11.6% and 16.8%, respectively) but increases in the median annual duration of exposure (7.4%). Amitriptyline had the highest proportion of single dispensings of all antidepressants throughout the study period (26.5% in 2015) and defined daily doses per person dispensed each medicine per year increased by 20% for antidepressants overall. Benzodiazepine use decreased across all measures over the study period apart from long-term use (exposure for >240 days of the year), which in 2015 was 23.6% of those dispensed a benzodiazepine. We observed a relative increase in the incidence and prevalence of antipsychotic use (14.2% and 26.8%, respectively), and haloperidol had the highest proportion of single dispensings of any antipsychotic throughout the study period (47.5% in 2015). We observed a relative increase in the incidence and prevalence of attention-deficit hyperactivity disorder medication use of 114.0% and 101.8%, respectively, over the study period. Conclusion: Increasing doses and treatment durations of antidepressants warrants further investigation due to concerns about overuse. Single dispensings of amitriptyline and haloperidol may indicate off-label use and long-term use of benzodiazepines remains problematic. Despite increases in attention-deficit hyperactivity disorder medication use, prevalence of use is still much lower than the estimated prevalence of attention-deficit hyperactivity disorder in the adult population.