Patients must not have a serious psychiatric illness (e.g. lifetime bipolar disorder, schizophrenia or other psychosis, serious personality disorder, severe major depressive disorder or recent suicide or psychiatric hospitalization) (previous 12 months), or a history of an eating disorder (anorexia nervosa or bulimia nervosa) Known central nervous system (CNS) metastases or seizure disorder; patients with known brain metastases that have been successfully treated and stable for >= 6 months without requirement for corticosteroids and without seizure activity will be eligible Active seizure or history of seizure disorder Patients with prior seizure history who have experienced a seizure within the three months prior to enrollment are excluded Patients with active seizure or history of seizure are not eligible Patients with seizure disorder may be enrolled if well controlled Patients with active seizure or a history of seizure are not eligible History of intractable epilepsy, or uncontrolled seizure disorder STEP I: Patients must not have active, uncontrolled seizure disorder; patients must have had no seizures in the last 6 months Patients receiving glucocorticoids and/or anti-seizure medications are eligible for this study Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients with a history of encephalitis, multiple sclerosis, or seizures within the last year (from seizure disorder or brain metastasis) should be excluded from this clinical trial Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients with uncontrolled seizure disorder are not eligible; (patients with seizure disorders that do not require antiepileptic drugs, or are well controlled with stable doses of antiepileptic drugs remain eligible) Patients considered at poor medical risk due to a serious, uncontrolled medical disorder, non-malignant systemic disease or active, uncontrolled infection; examples include, but are not limited to, uncontrolled ventricular arrhythmia, recent (within 3 months) myocardial infarction, uncontrolled major seizure disorder, extensive bilateral lung disease on high resolution computed tomography scan or any psychiatric disorder that prohibits obtaining informed consent Uncontrolled seizure disorder Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patient has no known history of seizure disorder Patients with a history of uncontrolled seizure disorder; including focal or generalized seizure may not have had a seizure within one year prior to registration Patients with seizure disorder may be enrolled if on anticonvulsants and if seizures are well controlled Patients with a high risk of seizures should be excluded from the protocol (e.g. those patients with an uncontrolled seizure disorder, and/or patients who have had a focal or generalized seizure within the last 12 months) Patients must not have active seizure or history of seizure Central nervous system function defined as:* Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled* Patients must not be in status epilepticus, a coma or on assisted ventilation at the time of study enrollment Active seizure disorder uncontrolled by medication Patients with seizure disorder requiring medication Patients with a seizure history will not be permitted on protocol; patients on anticonvulsant medications will not be permitted on study Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with active seizures or a history of uncontrolled seizure disorder, including focal or generalized seizure within the past year Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled