It was hypothesized that children’s levels of ADHD symptoms would remain
fairly stable from occasion 1 to 2, but then would show a clear decline from occasion 2 to 3 due to the effects of the stimulant medication
intervention. The Strengths and Difficulties Questionnaire (SDQ; Goodman,
2001) was also administered on occasions 2 and 3 in an attempt
to demonstrate the specificity of the stimulant medication intervention.
The fact that this questionnaire includes ADHD symptoms as well
as other problems (i.e., conduct problems, peer problems, and emotional
problems), made it possible to examine the methylphenidate intervention.
It was anticipated that more substantial treatment effects would be obtained
for ADHD-relevant symptoms (i.e., ADHD-Q and SDQ hyperactivity-inattention
scores) than for other symptoms.