Abstract
The outcome, merits, and limitations of the Multimodal Treatment Study for Children With Attention-Deficit Hyperactivity Disorder (ADHD), the MTA study, are described and discussed. Consideration is given to design issues that make the MTA a landmark study for clinicians and researchers working with ADHD children. These include the large, heterogeneous sample, the state-of-the-art treatment, the lengthy treatment period, the extensive documentation of treatment manuals, and the attention paid to treatment fidelity and adherence. Also highlighted are facets of the design that predisposed the study in favour of a differentially positive outcome for pharmacological relative to behavioural treatment. Primary among these is the fact that outcome was measured 4–6 months after the intensive phase of behaviour treatment and after therapeutic contact with the behaviour therapist had ended but while medication treatment was active and in its most intensive phase. Finally, the outcome for the combined treatment condition in the MTA is discussed in the context of the extant literature and directions for future research.