Psychotic symptoms are two to three times more likely to be experienced by individuals who have had a traumatic brain injury (TBI) than in the general population, but previous studies haven’t been able to indicate how traumatic brain injuries and psychosis are related. This condition is called Psychosis following traumatic brain injury (PFTBI). Batty et al. (2013) looked at 26 studies that explored the relationship between TBI and psychosis to help determine how traumatic brain injuries might influence the likelihood of experiencing delusions, hallucinations or disordered thoughts. The researchers found that traumatic brain injuries likely increase the chance of experiencing psychosis by the following mechanisms:
- Causing stress to a person who has a genetic predisposition to schizophrenia or other psychotic disorder, and increasing the likelihood they would experience those symptoms AND/OR
- Causing additional stress to a person who is experiencing environmental factors known to increase likelihood of psychosis ( ie. Low socio-economic status etc.) AND/OR
- Causing structural changes to the brain that parallel the changes in the brain exhibited by people with schizophrenia or other psychotic disorder, and thereby eliciting similar symptoms
The researchers emphasize that more than one factor could affect each person.
The article also identifies trends that have been identified across all 26 articles.
- Generally, increased severity of the brain injury, measured by the amount of cell death or length of time patient was unconscious after the injury, was related to increased risk of psychotic symptoms
- Most researchers found that symptoms in patients experiencing psychosis after a TBI mimic the same symptoms patients with schizophrenia exhibit: positive and negative symptoms as well as cognitive impairment, so it may be difficult to distinguish these symptoms from schizophrenia.
- People with psychosis following TBI typically experience deficits in language, vocabulary, verbal memory and verbal learning.
- EEG scans have shown that PFTBI patients typically have functional abnormalities in their temporal lobe, which might explain why there are deficits in language and verbal memory, specifically.
The authors of this study note that there are many problems associated with PFTBI research, for example, many participants are recruited from inpatient units, which means people with mild or moderate psychotic symptoms may not be included in research. In addition, participants with very different kinds of traumatic brain injuries are often all included in the same study, though the kind and severity of injury can have a significant influence on the severity of psychotic symptoms experienced. Caution should be taken when interpreting the results summarized in this article.
Batty, R. A., Rossell, S. L., Francis, A. J., & Ponsford, J. (2013). Psychosis following traumatic brain injury. Brain Impairment, 14(1), 21.
Maria Stacy, MA
WKPIC Doctoral Intern