Abstract / Summary
Abstract Aims Lisdexamfetamine, a long‐acting stimulant for attention‐deficit hyperactivity disorder (ADHD), has experienced widespread shortages in Australia since late 2023, raising concerns about treatment continuity and shifts in stimulant use patterns. This study assessed the impact of shortages in South Australia (SA) and Western Australia (WA) by triangulating prescription dispensing and wastewater‐based epidemiology (WBE). Methods Monthly Pharmaceutical Benefits Scheme (PBS) dispensing data for lisdexamfetamine and dexamfetamine were converted to defined daily doses (DDD) per 1000 population per day. Concurrently, bimonthly wastewater samples from metropolitan sites were analysed for amphetamine and methamphetamine concentrations, with methamphetamine serving as a control as its use was unlikely to be affected by the shortage. Data were compared from February 2022 to December 2024. Results In WA, lisdexamfetamine DDDs increased from 5.59 to 13.02 and dexamfetamine from 2.55 to 6.03 per 1000 population per day, doubling combined stimulant DDDs from 8.14 to 19.05. In SA, lisdexamfetamine DDDs rose from 1.05 to 5.00. Wastewater amphetamine levels fluctuated (WA: 5.07–17.10; SA: 0.79–3.46 doses/day/1000 people) but declined sharply during shortages, while methamphetamine levels remained high (peaking at 62.65 in WA and 66.22 in SA). Conclusions Triangulation revealed variations in lisdexamfetamine use during shortages and highlighted potential behavioural responses. While these behaviours may partly explain differences between prescription dispensing and wastewater amphetamine levels, they do not fully account for the observed temporal patterns. Nonetheless, triangulating these data sources offers valuable insights for monitoring medicine use and informing public health and policy responses during supply disruptions.