Participants in this double-blind study will attend an initial screening during which they will undergo a physical exam, an electrocardiogram, and blood and urine collection. Participants will then be randomly assigned to receive galantamine and CDP-choline or a placebo treatment for 16 weeks. Participants assigned to the treatment group will take 500 mg of CDP-choline daily for the first 3 days, 1,000 mg daily for the next 4 days, and 2,000 mg daily for the following 15 weeks. Participants assigned to the treatment group will also take 8 mg of galantamine daily for the first week, 16 mg daily for the next week, and 24 mg daily for the following 14 weeks. Participants assigned to the control group will take two types of placebo pills every day for 16 weeks. All participants will continue to take their regular regimen of risperidone, olanzapine, quetiapine, ziprasidone, and/or aripiprazole throughout the trial in addition to their assigned treatment. Staff members will meet with participants during the first week of the study and every 4 weeks afterward until study completion. During these meetings, participants will identify any side effects, report nicotine intake, breathe into a machine that measures the amount of nicotine in the body, and complete written and computerized tasks on concentration and memory. Each meeting may last up to 3 hours. On the last week of the study, blood and urine samples will be collected and an electrocardiogram will be administered. Results from this study will be used to evaluate whether CDP-choline and galantamine improve schizophrenia symptoms.