SPD489 Low Dose and High Dose Ranges When Added to Stable Doses of Antipsychotic Medications in Clinically Stable Adults With Negative Symptoms of Schizophrenia

Inclusion Criteria: * \- 18 to 65 years of age * Has a reliable informant (eg, family member, social worker, caseworker, or nurse that spends \>4 hours/week with the subject) * Fixed home/place of residence and can be reached by telephone * On a stable dose of antipsychotic medications * Able to swallow capsules Exclusion Criteria: * Taking lithium, carbamazepine, lamotrigine, gabapentin, cholinesterase inhibitors, modafinil, or other stimulants such as methylphenidate and other amphetamine products * Treated with clozapine in past 30 days * Lifetime history of stimulant, cocaine, or amphetamine abuse or dependence * History of seizures (other than infantile febrile seizures), any tic disorder, or current diagnosis and/or a known family history of Tourette's Disorder, serious neurological disease, history of significant head trauma, dementia, cerebrovascular disease, Parkinson's disease, or intracranial lesions * Uncontrolled hypertension * History of thyroid disorder that has not been stabilized on thyroid medication * Glaucoma * Pregnant or nursing * Subject has received an investigational product or participated in a clinical study within 30 days