By Brenton Prosser and Yogi Vidyattama
The number of young people in Australia prescribed medication for attention-deficit hyperactivity disorder (ADHD) increased more that tenfold in 20 years, our new research shows, while it is no longer most prevalent in poorer areas.
Children living in the lowest socioeconomic postcodes used to have the highest rates of ADHD prescriptions. But this has flipped, with kids from wealthier families now most likely to be prescribed.
So does this mean ADHD prescription depends on how much your parents earn?
Not quite. Overall, the variation in prescription levels has narrowed around the national average over the last 20 years. But there is a stark difference between the most and least wealthy postcodes.
What is ADHD?
ADHD is the most commonly diagnosed disorder among Australian children. While symptoms vary from person to person, it’s associated with hyperactive and/or inattentive behaviours that cause challenges at home, school or work.
The most common approved treatment for ADHD is psychostimulant drugs.
What we studied
Our research team went back through two decades of national data from 2003 to 2022. We looked at official prescription records from Australia’s Pharmaceutical Benefits Scheme (PBS), which subsidises medication.
We wanted to find out how prescription rates change and differ between states and territories. We also wanted to know whether living in a wealthy or disadvantaged postcode plays a role in accessing prescription.
To look at ADHD prescriptions by postcode, we used an established way of comparing postcodes by calculating something called a “standardised medication ratio”.
If a postcode had the national average rate of prescriptions, its score was 1.0. Higher than one means more prescriptions than average, lower means fewer.
What we found
Between 2003 and 2022, the number of children aged 5–17 on ADHD medication increased from 20,147 people (0.5 percent of the youth population) in 2003 to 246,021 young people (or 4.2 percent) in 2022.
The biggest jump was in 2020 and 2021 during the COVID pandemic, when prescriptions spiked, especially for older teens (15–17 years), up by 2.1 percentage points from 3.1 percent in 2020 to 5.2 percent in 2022.
Lockdowns seem to have pushed more families to get help or at least start paying more attention to neurodivergence and learning issues.
Back in the 1990s, your chances of getting ADHD medication really depended on where you lived or how much your parents earned.
Some states, such as Queensland and Western Australia, were prescribing more than others. As our data shows, rates were higher still in Western Australia and Tasmania in 2003.
When standardising for populations (adjusting for the number of children living in a postcode), we can see how this trend varied by state and territory over the 20 years.
Over time the differences have narrowed.
This suggests clinicians are becoming more consistent in how they diagnose and treat ADHD. This is largely the result of the efforts to standardise best practices across the nation and remove the big variations of 20 years ago.
As some states and territories expand prescription to GPs, robust training and standardisation will be vital to avoid some of the past inconsistencies.
So how does wealth come into it?
For a long time in Australia, it was the kids in the most disadvantaged areas who were more likely to be prescribed ADHD medications.
This may have been because behaviour symptoms can stand out more when schools and families have fewer resources to manage them.
But this pattern has flipped. These days, it’s the wealthiest postcodes – the top 10 percent – where kids are most likely to be prescribed medication.
In 2003, richer areas were least likely to have kids medicated for ADHD, with a ratio of 0.612 (remembering that 1.000 is the national standard). By 2021, they’d climbed all the way to the top with a ratio of 1.245.
At the time, seven of ten deciles had ratios between 0.948 and 1.039, while the lowest 10 percent of postcodes had a ratio of 0.708.
Why the switch?
It probably has a lot to do with access. Twenty years ago, we did not see today’s level of demand and the health system could largely cover the demand.
Now, getting a diagnosis can take multiple specialist appointments, psychological assessments and possibly months on a waiting list. The poorest families might face longer waits or may not pursue diagnosis and medication at all if it feels out of reach.
However, this data shows that, on average, most postcodes now sit close to the national average. So, it’s only the very top and very bottom income groups that have flipped in twenty years.
The limits of the data
It’s important to note a few caveats. The data only includes prescriptions filled in the PBS system. That means prescriptions from the private medical system are not included, which means the trend in the highest postcodes may be even higher.
The study also couldn’t look at the influence of culture or ethnicity, since the data was anonymous.
And while stimulants are mainly prescribed for ADHD, a tiny number are used to treat other conditions (such as narcolepsy).
Diagnostic guidelines have shifted over the years, most notably when guidelines changed to allow diagnosis of ADHD and autism in 2013, but this did not result in a notable jump in prescriptions in our study.
The real growth came steadily over time, then sped up around COVID since 2020.
Importantly, the study didn’t look at how many repeat prescriptions were taken each year or compare individual postcodes to the national rate, so it does not speak to whether ADHD is being overdiagnosed or overmedicated in some postcodes.
What does it all mean?
Our findings show more people are accepting ADHD and getting help. This points to better acceptance of neurodivergence, more consistent care, and a society trying help all its kids thrive in new and changing times.
More standardised practices and consistent care means we’re moving away from the “postcode lottery” effect, where treatment depends too heavily on where you live.
However, the flip in highest diagnosis ratios from the poorest postcodes to the richest means we still need to look closely at access and equity of treatment.
Brenton Prosser is a Partner, Government & Public Sector, Providence / Honorary Fellow at the Australian National University. Yogi Vidyattama is an Associate Professor, Faculty of Business, Government and Law at the University of Canberra. This article was first published by The Conversation
