D-MPH in the Treatment of Fatigue and Neurobehavioral Function Related to Chemotherapy in Adult Cancer Patients

* Diagnosis of cancer, excluding primary or metastatic brain tumors. * Treated with a minimum of four cycles of a cytotoxic chemotherapy, the last chemotherapy treatment must have been completed at least 2 months prior to study entry. * Physical/neurological examination consistent with the absence of a focal neurological deficit * Women of childbearing potential (WCBP) must have a negative serum or urine pregnancy test. In addition, sexually active WCBP must agree to use adequate contraceptive methods (oral, injectable, or implantable hormonal contraceptive; tubal ligation; intra-uterine device; barrier contraceptive with spermicide; or vasectomized partner). * Subjects must be able to adhere to the protocol requirements. * Subjects must understand and voluntarily sign an informed consent document. * Subjects must be a native English speaker or fluent in English, and have at least an eighth grade education.