Efficacy and Safety of SPD503 in Combination With Psychostimulants

You may be eligible if

• Healthy subjects with ADHD currently taking a stable dose of psychostimulant for at least 4 weeks
• Aged 6-17 years with a sub-optimal
• Partial response to stimulants
• Subjects must be \< 95th percentile for BMI with weight \>= 55lbs and \<= 176lbs