The results of a meta-analysis examining the effect of amphetamines and methylphenidate in the treatment of attention deficit hyperactivity disorder (ADHD) were announced at the International ADHD Congress in Vienna in May.

The study included 23 placebo-controlled trials examining hyperactive, inattentive or impulsive behaviour in children and adolescents. The study found that the effect size, measured as standardised mean difference (SMD) was significantly greater for amphetamines than for methylphenidate formulations (1.10 vs 0.79, p=0.003).

One of the amphetamines included in the meta-analysis was the long-acting pro-drug lisdexamfetamine dimesylate, and the first Phase 3 European trial to investigate its efficacy in children and adolescents with ADHD was also announced at the congress. The initial results of the trial are hoped to be presented in 2010. Lisdexamfetamine dimesylate is currently licensed in the USA for the treatment of ADHD in children and adults but is not yet licensed in the European Union.