Paranoia--an unusual presentation of hydrocephalus.

Hydrocephalus commonly occurs after traumatic brain injury. Normal pressure hydrocephalus after traumatic brain injury is usually associated with a failure to progress in therapy and a plateauing or regression of functional abilities. Behavior disturbances are commonly seen as unfortunate sequelae of traumatic brain injury. However, normal pressure hydrocephalus has not been reported to cause aberrant, antisocial behavior. This case report details the course of a patient who sustained a traumatic brain injury and, subsequently, developed normal pressure hydrocephalus associated with paranoia, delusions, and violent behavior.