Carbamazepine for the Treatment of Chronic Post-Traumatic Brain Injury Irritability and Aggression

Inclusion Criteria: * Closed head injury (defined as impaired brain function resulting from externally inflicted trauma without penetrating injury) at least 6 months prior to enrollment * Age at time of enrollment: 16 to 75 years * Voluntary informed consent of patient and informant * Subject and informant willing to comply with the protocol * Informant-rated NPI Irritability Domain score 6 or greater to include only moderate-severe irritability * Medically and neurologically stable during the month prior to enrollment If taking antidepressant, anxiolytic, hypnotic, or stimulant medications, no change anticipated in these medications during the month prior to enrollment No change in therapies or medications planned during the 42-day participation No surgeries planned during the 42-day participation Vision, hearing, speech, motor function, and comprehension sufficient for compliance with all testing procedures and assessments * Informant (e.g. family member or close friend) with daily interaction in order to observe occurrences of irritability Exclusion Criteria: * Potential subject without a reliable informant * Penetrating head injury * Injury \< 6 months prior to enrollment * Ingestion of carbamazepine during the month prior to enrollment * Inability to interact sufficiently for communication with caregiver * Acute and rehabilitation records unavailable or incomplete * Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) diagnosis of schizophrenia or psychos…