Inclusion Criteria:

          -  Have diagnosis of prostate cancer and have received treatment with GnRH agonist or
             antagonist therapy for at least 1 month prior to enrollment.

          -  Willing and able to complete survey questionnaires in English without assistance
             through the duration of the study. This stipulation is in place because not all of the
             proposed quality of life or cognitive tests are available or validated in other
             languages.

          -  Age ≥ 18 years.

          -  Ability to understand and the willingness to sign a written informed consent document
             written in English that is approved by an institutional review board.

          -  Have either newly diagnosed metastatic hormone sensitive prostate cancer (mHSPC) or
             castration-resistant metastatic prostate cancer (mCRPC) and eligible to undergo
             treatment with abiraterone acetate (mHSPC or mCRPC) or enzalutamide (mCRPC)

          -  Patients may have received the following prior AR directed therapy prior to
             enrollment: bicalutamide, ketoconazole. Prior to enrollment, patients may have
             received treatment with abiraterone acetate or enzalutamide for no more than 14 days
             before completing baseline studies.

          -  Patients may have received chemotherapy for hormone-sensitive metastatic prostate
             cancer only, but it must not have lasted for more than 6 months. At least 12 months
             must have elapsed since completion of chemotherapy.

          -  Patients may have received prior definitive radiation therapy or surgery. At least 60
             days must have elapsed since completion of definitive radiation therapy or surgery and
             patient must have only grade 2 or less adverse effects at the time of registration.
             Enrollment during palliative radiation of ≤ 10 days, or radiation of ≤ 10 days during
             the duration of the study is allowed.

          -  Patients must be able to take oral medication.

        Exclusion Criteria:

          -  Prior treatment with enzalutamide or abiraterone acetate for > 14 days prior to
             enrollment and completion of baseline tests.

          -  Receipt of chemotherapy for prostate or other cancer within the past 12 months with
             residual cognitive deficits, or receipt of chemotherapy for mCRPC. Patients/physicians
             planning treatment with chemotherapy during the 12 month period of the investigation
             are also ineligible.

          -  History of cognitive impairment or dysfunction, including a history of dementia,
             Alzheimer's disease, stroke with residual cognitive deficits, cognitive dysfunction
             related to alcohol or substance abuse, or cognitive dysfunction related to prior
             treatment for any cancer.

          -  Patients with a seizure history, history of recurrent falls, or known brain metastases
             are excluded from this clinical trial because of their poor prognosis and because of
             their heightened risk of seizure or progressive cognitive and/or neurologic
             dysfunction that would confound the evaluation.

          -  Uncontrolled intercurrent illness including, but not limited to, uncontrolled
             diabetes, ongoing or active infection, symptomatic congestive heart failure (New York
             Heart Association Class III and IV heart failure), unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations/substance abuse that would limit
             compliance with study requirements.

          -  Patients with a "currently active" second malignancy other than non-melanoma skin
             cancers are not eligible. Patients are not considered to have a "currently active"
             malignancy if they have completed all therapy and are now considered without evidence
             of disease for 1 year. Patients with cognitive dysfunction related to treatment of
             another malignancy, including a history of "chemo-brain", are ineligible.

          -  Patients taking psychotropic medications or illicit drugs that may alter cognition,
             concentration, or behavior. Appropriate treatment by a licensed provider with
             medications for depression or anxiety, including but not limited to SSRIs, SNRIs, and
             standard dose benzodiazepines at a stable dose, is permitted