Evaluate the Effects of Tolcapone on Cognitive and Behavioral Dysfunction in Patients With BI and NCD

Each patient will receive a two-week specified dosing amount of tolcapone (100mg TID on Day 1; 200mg TID on Days 2-14). The patient will be instructed to take the study drug three times daily. Tolcapone will be tapered after Day 14 to avoid potential withdrawal reactions. Clinical Instruments for patients: * Question banks from large patient-reported outcome measure initiatives will be used and administered and used by computerized-adaptive tests (CATs). These include the TBI-QoL for patients with TBI and question banks from the patient-reported outcome measure information systems (PROMIS) and neurology quality of life measurement initiative (Neuro-QoL). Patients will answer questions related to their mobility, fatigue, pain interference, positive affect and well-being, depression, anxiety, anger and irritability, and emotional and behavioral dyscontrol. * Clinical Global Impressions Scale * Geriatric Depression Scale-15 * State-Trait Anxiety Inventory * Hopkins Adult Reading Test * Frontal Systems Behavior Scale * Montreal Cognitive Assessment * Trails A\&B * Modified Wisconsin Card Sorting Test * NIH Toolbox * Perceptual Comparison Test * Brief Test of Attention * Hopkins Verbal Learning Test * Brief Visuospatial Memory Test * Calibrated Ideational Fluency Assessment * Profile of Mood States * Digit Span Clinical Instruments for Informants: * Neuropsychiatry Inventory * Apathy evaluation scale * Overt aggression scale * Frontal Systems Behavior Scale Laboratory Measures: * Blood sample for genotyping * Blood sample for assessing COMT activity. * Blood sample for a laboratory profile including CBC, CMP, TSH, Hepatitis Panel (B and C), and RPR * A urine analysis, urine drug screen, and a urine pregnancy test * In addition for NCD patients: a blood sample for tests including Serum Calcium, B12, ESR, and C-reactive protein