2.2 | Study measures
Outcomes of interest included the dispensing of antipsychotic medications, antidepressants, anxiolytics, and hypnotics. The PBS item code of each medication dispensed between 2013 and 2022 was linked to the following Anatomical Therapeutic Chemical (ATC) codes: N05A for antipsychotics, N06A for antidepressants, N05B for anxiolytics, and N05C for hypnotics.6 We stratified age into the following groups: 0-9, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89, and ≥ 90 years. Sex was recorded as male or female. We used published estimates for the fraction of the population dispensed medications during the 2020-2021 period:7 0-9 years, 45.9%; 10-19, 45.9%; 20-29, 54.4%; 30-39, 57.5%; 40-49, 65.7%; 50-59, 69.1%; 70-79, 92.4%; 80-89, 98.0%; ≥ 90 years, 99.0%.