Psychotic disorder following traumatic brain injury: a conceptual framework.
BACKGROUND
Psychotic Disorder Following Traumatic Brain Injury (PDFTBI) is a relatively rare disorder that may provide clues to understanding schizophrenia and psychosis. The objective of this paper was to develop a conceptual framework describing how traumatic brain injury (TBI) can contribute to the development of a psychosis and potential neurobiological mechanisms that cause a psychosis in this population.


METHODS
The literature on PDFTBI and previous conceptualisations of the disorder were reviewed. A model of psychosis was described as a context for a conceptualisation of PDFTBI.


RESULTS
PDFTBI is associated with abnormalities to the temporal and frontal areas. The general presentation includes persecutory delusions and auditory hallucinations with an absence of negative symptoms. The mean onset is 4-5 years after TBI with the majority of cases occurring within 2 years. The progression and course of PDFTBI is variable. Neuroleptics appear to be the most efficacious medication. Previous conceptualisations of PDFTBI are varied and suggest that the relationship is not a simple one.


CONCLUSIONS
We propose that psychosis results from damage to the frontal and temporal areas and dysregulation of the dopaminergic system. Everyone is vulnerable to a psychotic disorder and psychosis will result when a threshold of damage to these areas are attained. Traumatic brain injury can be the primary cause of psychosis or contribute to the development of a psychosis through secondary seizure disorder, increasing biological and psychological risk, and triggering psychosis in vulnerable patients. The relationship may also be coincidental. Traumatic brain injury triggers pathophysiological processes that generally result in a psychosis after a delay of 1-5 years. Directions for future research includes prospective studies examining the impact of TBI on developing psychosis, retrospective studies examining TBI as a risk factor in schizophrenia or other populations at risk for secondary psychosis, and studies examining prevention of psychotic illness.
Department of Neuropsychology, Hawaii State Hospital, Kaneohe 96744, USA. defujii@hsh01.health.state.hi.us
Daryl
D
Fujii
Iqbal
I
Ahmed