The objective of this study is to evaluate the long-term effects and tolerability of ABT-089 in adults with Attention-Deficit/Hyperactivity Disorder (ADHD).

Inclusion Criteria:

• The subject was randomized into Study M10-346 and completed the study.
• Female subjects of childbearing potential must have a negative urine pregnancy test at screening and baseline and agree to comply with applicable contraceptive requirements.
• Male subjects must agree to comply with applicable contraceptive requirements.
• The subject is judged to be in generally good health.

Exclusion Criteria:

• The subject has taken any ADHD medication between the last dose of study drug in Study M10-346 and the first dose of study drug in the current study.
• The subject anticipates a move outside the geographic area.