3. Subjects must have greater than or equal to 10 lifetime nontherapeutic experiences with central nervous system (CNS) stimulants (e.g., amphetamines, cocaine, methylphenidate), greater than or equal to 1 nontherapeutic use of prescription stimulants within the 12 months prior to Screening, and greater than or equal to 1 nontherapeutic use of a CNS stimulant within the 12 weeks prior to Screening.