Objective: There is a need for Australian studies of ADHD that utilize the individual child as the unit of analysis because they provide a more accurate picture of national patterns (in new prescriptions, start age, and duration). The aim of this study was to build toward a national picture of patterns in psychostimulant use for ADHD by undertaking a retrospective analysis of archival data on prescriptions within New South Wales (NSW), Australia’s most populated state. Method: A person-based data set was used to assess (a) rate of new prescriptions by age group, (b) demographic characteristics (age of start, male:female ratio), (c) duration of use, and (d) comparisons across the two decades. Results: Five findings were observed: (a) The prevalence of psychostimulant use was 1.24% in 2010, (b) there was significant variability in the rate of new prescriptions by age group after 2003, (c) start age declined over the 1990 to 2000 period, but began to increase from 2000 to 2010, (d) the male:female ratio declined, and (e) the duration of psychostimulant use declined consistently. Conclusion: Results suggest disconnect between persistence across the life span and actual treatment patterns. A decline in medication treatment for more than 1 year and the growing proportion of discontinuous treatment suggests a need for strategies to assist families with the transition onto and off medications.