Buspirone for the Treatment of Traumatic Brain Injury (TBI) Irritability and Aggression

Inclusion Criteria: * Closed head injury (impaired brain function resulting from externally inflicted trauma without penetrating injury as defined below) at least 6 months prior to enrollment * Irritability that is either new or worse than level of irritability before the traumatic brain injury, by report of observer or person with TBI * Age at time of enrollment: 18 to 70 years * Voluntary informed consent of patient and observer * Subject and observer willing to comply with the protocol * Observer-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 91-day participation * No surgeries planned during the 91-day participation * Vision, hearing, speech, motor function, and comprehension sufficient for compliance with all testing procedures and assessments * Observer (e.g.: family member, close friend, employer) with whom subject interacts sufficiently to observe occurrences of irritability. The observer interacts with the participant for a period long enough and of a nature to be able to judge the participant's irritability. The interactions would need to be adequate to judge observer distress over the irritability, severity of irritability and frequ…