Every 15 seconds, someone in the United States suffers a traumatic brain injury. Of the 1,000,000 people treated in hospital emergency rooms each year, 50,000 die and 80,000 become permanently disabled because of traumatic brain injury….
Many psychiatric delusions appear to be associated with mild traumatic brain injury. Examples include content- specific personality changes, such as when the patient believes that family members are impostors or identical doubles. An extremely common delusion among domestic abusers and stalkers is pathological jealousy and preoccupation with another person.
Brain injury causes lesions that appear and change over time in the prefrontal cortex and its pathways to the older regions of the brain. This explains the wide spectrum of complex neurobehavioral complaints following minimal traumatic brain injury: compulsive and explosive behavior, sensory anomalies, memory loss—as well as behavioral disinhibition, domestic violence, and alcohol intolerance.
—"The Human Brain," website of the Franklin Institute Science Museum