2.3 | Statistical analyses
We calculated the total count and proportion of participants in each age group who had been dispensed an antipsychotic antidepressants, anxiolytic, or hypnotic between 2013 to 2022 during each of these years. We evaluated the effect of time, age, and sex on the dispensing of these medications using logit models for the analysis of panel data. The results of these analyses were summarised by the odds ratio (OR) and respective 99.9% confidence interval (99.9%CI). Reference groups were 2013, age 0-9 years, and male sex. Because of the very large sample and the risk of type I error, we set alpha at 0.1% (p≤0.001). All tests were two-tailed.
3 | RESULTS
The PBS file included 16,389,245 records (Table 1). Of all records, 54.10% were for females. Figure 1 shows the proportion of participants dispensed antipsychotics, antidepressants, anxiolytics, and hypnotics between 2013 and 2022. There was a decline in the proportion of people dispensed antipsychotic medications over time, most noticeably amongst those aged ≥ 80 years. The dispensing of antipsychotics was highest among those aged 80-89 and 90 years or over. There was minimal difference between the age groups 30 to 69 years in the dispensing of antipsychotics. About 1 in every 6 people in the PBS database were dispensed an antidepressant. The 80-89 and ≥90-year age-groups were the most frequently dispensed antidepressants. There was a progressive rise in the proportion of people dispensed antidepressants over time, with a noticeable sharp increase after 2019 among people aged 10-19 (8.36% from 2013 to 2022), 20-29 (9.87% from 2013 to 2022) and 30-39 years (4.44% from 2013 to 2022). The dispensing of anxiolytics was highest among the older age groups, although the proportion of people aged 60 years or over dispensed anxiolytics declined with time, particularly after 2014. A similar pattern of dispensing was observed for hypnotics. The odds of females being dispensed an antipsychotic were lower compared with males (OR=0.74, 99.9%CI=0.72-0.76), but higher for the dispensing of antidepressants (OR=2.71, 99.9%CI=2.66-2.77), anxiolytics (OR=1.58, 99.9%CI=1.55-1.61), and hypnotics (OR=1.60, 99.9%CI=1.57-1.64).
As the proportion of the population issued medication scripts is relatively low among young people, we adjusted our calculations for the estimated likely denominator for the relevant age-group.7 The results of these analyses are displayed in Figure 1. The proportion of Australians aged 10-19, 20-29 and 30-39 years dispensed antidepressants increased from 2.92% to 5.93%, 7.74% to 12.44%, and from 10.13% to 12.65% between 2013 and 2022.
4 | DISCUSSION
Our results show that a large proportion of Australians accessing community pharmacies are dispensed psychotropic medications, antidepressants being the most frequent among them. We found that older adults, most noticeably those aged 80 years or over, were the most frequent recipients of antipsychotics, antidepressants, anxiolytics, and hypnotics, although the proportion of older adults dispensed antipsychotics, anxiolytics and hypnotics has declined over the past 10 years, particularly after 2015. We also found that an increasing proportion of participants were dispensed antidepressants between 2013 and 2022, with the most marked rise occurring amongst those aged 10-19 and 20-29 years. A larger proportion of females than males were dispensed antidepressants, anxiolytics, and hypnotics, but a greater proportion of males than females were dispensed antipsychotics, albeit not in later life.
Access to the large PBS database allowed us to examine the dispensing patterns of medications in Australia between 2013 and 2022, with evidence from other sources suggesting that the agreement between dispensing and medication use is high.8 One important caveat of this dataset is that the numbers reflect only the people who have been dispensed a medication during the relevant time-period (not necessarily a psychotropic drug). This is the case for about 54% of people aged 0-17 years, but only 2% of those aged 80 years or over.7 As a result, prevalence estimates are likely to be inflated for the population of young and middle-aged people, but should be relatively accurate for older people. Hence, the observed discrepancy in the use of psychotropic medications between older and younger people could be even more pronounced than our calculations using the crude PBS data suggest. Our additional analyses yielded results that are consistent with this hypothesis (Figure 1).
The proportion of people dispensed antipsychotics, anxiolytics and hypnotics declined over the 10 years of the study, but the proportion of those receiving antidepressants increased. This rise in the proportion of people dispensed antidepressants has been observed in some,9 but not all, countries,10 and has recently been portrayed as a consequence of the COVID-19 pandemic or, alternatively, of stockpiling of medications triggered by uncertainty surrounding the medium and long term consequences of lockdowns.11 Our analyses suggest that stockpiling is an unlikely explanation for our findings, as rises in the dispensing of psychotropics were not apparent for other medication classes. They also suggest that the pandemic may have affected the mood of adolescents and young adults more markedly, although upwards trends in the dispensing of antidepressants had been apparent for at least five to six years earlier. Such a change may reflect an increase in the prevalence of mood disorders in the community (particularly among adolescents and young adults),12 changes in diagnostic practice,13 or a shift in prescription habits that have led to progressively greater use of antidepressants for the management of conditions other than depression (such as anxiety disorders).14 The concurrent decline in the use of other psychotropic medications could further be viewed as an indication that the dispensing of antidepressants may be increasingly used for the management of conditions other than depressive disorders. In addition, sex differences in the dispensing of psychotropics may have been due to real discrepancies in the prevalence of mental health disorders treated by these medications, or may represent differing gender-mediated help-seeking behaviours.15
In conclusion, our results indicate that older adults and females have been, and continue to be, the most frequent recipients of psychotropic medications dispensed in Australia over the past decade. The organisation and resourcing of health services should reflect this reality.
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FIGURE LEGEND
Figure 1. The figure shows the proportion (%) of people included in the 10% PBS database who were dispensed antipsychotics (top left), antidepressants (bottom left), anxiolytics (top right), and hypnotics (bottom right) between 2012 and 2021 according to their age groups (coloured lines). The estimates depicted in the figure were adjusted for the proportion of people expected to have been missed in each age-group because they were not included in the PBS database.7