The purpose of this study is to assess the safety and effectiveness of SPD465 in the treatment of ADHD. The study will also look at how SPD465 affects sleep.

Inclusion Criteria:

• Subject satisfied all entry criteria for the antecedent protocol (SPD465-301 or SPD465-303) and completed a minimum of 4 of the 7 weeks of double-blind treatment without experiencing any clinically significant adverse events.
• Subject must be male or non-pregnant female who agrees to comply with using acceptable contraceptive methods.

Exclusion Criteria:

• Subject was terminated from antecedent protocol (SPD465-301 or SPD465-303) for non-compliance and/or experienced a serious adverse event or adverse event resulting in termination from the protocol.
• Comorbid psychiatric diagnosis with significant symptoms such as Axis II disorders or severe Asix I disorders.
• History of seizure, tic disorder, or a current diagnosis and/or family history of Tourette's Disorder.
• Females who are pregnant of lactating.