Traumatic Brain Injury Boosts Risk of Schizophrenia

A recent study conducted by researchers from the Royal College of Surgeons in Dublin indicates that traumatic brain injury (TBI) may be linked to an increased risk of developing schizophrenia.

TBI is caused by a serious blow to the head which may or may not penetrate the skull; known to cause severe damage, TBI can result in a concussion, memory loss, loss of consciousness, problems with motor coordination, depression, and even amnesia, in rare cases. TBI is also known to be connected to an elevated risk of certain psychiatric disorders, including anxiety disorders, substance use disorders, and personality change.

Mary Cannon—a professor of psychiatry at the Royal College of Surgeons—and her fellow colleagues reviewed nine studies performed prior to this one, all of which included participants who had suffered TBI and a control group of participants who had not suffered from TBI.

After analyzing the data from these studies, the researchers found that TBI was, overall, linked to an increased risk of schizophrenia. Participant who had suffered from TBI were found to be 1.6 times more likely to become schizophrenic than individuals who had not suffered from TBI; in cases of a participant with a family history of schizophrenia, the risks were elevated to 2.8 times more likely.

The researchers noted that the risk of schizophrenia did not elevate in correlation to the severity of the brain injury, indicating that other factors—location of the trauma, particularly—may be more connected to the increased risk of developing the psychiatric disorder. Unfortunately, the researchers did not take into account the location of the traumatic brain injury in their study.

A limitation of this study is that the researchers did not gather new research, reported Dolores Malaspina, a professor of psychiatry and environmental medicine at New York University who was not involved in the study. Still, said Malaspina, the studies the researchers reviewed in the new analysis are "excellent.”

Schizophrenia affects roughly 1.5% of the global population. Generally, the symptoms included delusions, auditory hallucinations, disorganized speech and thinking, and considerable social or occupational dysfunction.

Malaspina stated that a possible explanation for the results of this study could be attributed to the fact that some people may be genetically predisposed towards schizophrenia, in which case all that is necessary is a trigger event—such as TBI—to activate the disorder. "Exposure to a brain injury in those people can unmask a psychotic illness,” said Malaspina.

The researchers were careful to stress that their work only shows a link between TBI and schizophrenia, and there is no proof that TBI causes the condition. They continued to say that more work needs to be done in order to discover what mechanism is responsible for the connection between TBI and schizophrenia.

This study was published in the journal Schizophrenia Bulletin.