Patterns of psychostimulant prescribing to children with ADHD in Western Australia: variations in age, gender, medication type and dose prescribed.

OBJECTIVE: To examine treatment with psychostimulant medicines for attention deficit hyperactivity disorder (ADHD) in children (3-17 years) within Western Australia (WA) during 2004.

METHODS: Using whole-population-based administrative pharmacy data for 2004, age-specific prevalence of children treated with dexamphetamine and methylphenidate was determined. Treatment with immediate-action and sustained-release stimulants was also examined. Average daily dose (absolute and relative to body weight) of dexamphetamine, methylphenidate and total stimulant medication was also calculated.

RESULTS: 9,658 children from 3-17 years (23.5 per 1,000 child population) were treated with stimulant medication for ADHD during 2004. Age-specific prevalence of treatment increased rapidly from three to eight years to peak at 14 years. The male-to-female ratio of stimulant treatment was 4.1. Child prevalence of treatment with dexamphetamine, methylphenidate or combined therapy was 16.4, 8.9 and 1.7 per 1,000 children, respectively. Most children were treated with immediate-action stimulants (16.9 per 1,000 child population), with fewer using sustained-release medicines (4.0 per 1,000 child population).

CONCLUSIONS: The prevalence of stimulant medication use for the treatment of ADHD in WA children is 2.4%, with males accounting for the majority of treated patients. Most children were treated with dexamphetamine. Prescribing of methylphenidate, sustained-release stimulants or combined medication therapy was less common. Age-related trends in prescribed daily dose differed for dexamphetamine and methylphenidate.