Traumatic Brain Injury May Be a Risk Factor for Schizophrenia

Mental disorders are one of the most common outcomes of traumatic brain injury (TBI). About 1 in 3 individuals who sustain a TBI will develop depression in the following six months, and about half will develop depression within a year. Furthermore, half of those with post-injury depression will also experience generalized anxiety.

Ample research has supported the development of clinical prevention and treatment efforts for these disorders, which can be debilitating and may interfere with the injury recovery process. However, fewer efforts have focused on the incidence of other mental disorders that are less common following TBI—but no less devastating. Among these rarer outcomes is schizophrenia, a serious psychiatric condition that can impair everyday functioning and may substantially reduce an individual’s quality of life.

What Is Schizophrenia?

Schizophrenia is a psychotic disorder that affects a person’s cognition, mood, social functioning, and behavior. Psychotic symptoms typically include delusions, paranoia, hallucinations, and changes in thinking and speech patterns. The disorder is also characterized by anhedonia; low motivation; impaired emotional expression; and cognitive deficits, including impairments in memory, attention, and concentration.

Taken together, these symptoms may cause a person with schizophrenia to experience a distorted sense of reality, which can compromise their ability to engage in daily life and may cause significant distress to the sufferer and their loved ones. Fortunately, treatments like antipsychotic medications and psychotherapy usually manage schizophrenia to the degree that affected people can successfully engage in activities of daily living, such as work, school, and social relationships.

Onset of schizophrenia usually occurs in adolescence through early adulthood, and it is widely understood to be the result of a strong genetic predisposition towards the condition. In fact, estimates suggest that the heritability of schizophrenia is 0.79, meaning that about 79% of schizophrenia cases can be accounted for by genetic differences across individuals. However, not all people who are genetically predisposed to schizophrenia will develop the disorder. Physical and environmental factors, such as life stressors, can trigger the set of genes associated with schizophrenia and other psychotic disorders, leading to onset of the condition.

Is Traumatic Brain Injury a Trigger of Schizophrenia?

Recent evidence suggests that TBI may be one such trigger of schizophrenia. A landmark literature review found that people who sustained a TBI were 60% more likely to develop schizophrenia, and risk was doubled among people who were already predisposed to schizophrenia based on a family history of the disorder. Injury severity was not associated with the likelihood of developing schizophrenia, indicating that even people who experience a mild TBI, or concussion, may be at substantially elevated risk for the condition compared to the general population. Among post-TBI schizophrenia patients, the most common symptoms were delusions and hallucinations, the latter of which were more common among individuals who developed schizophrenia more than two years after the injury.

Importantly, while these findings do indicate a significant association between TBI and schizophrenia, the causal relationship remains unclear. Experts have pointed out that people with underlying risk for schizophrenia, even before the condition emerges, may be at higher risk of engaging in risky activities that can lead to TBI, such as substance use. In this case, schizophrenia itself would act as a risk factor for TBI. Most researchers posit that both schizophrenia and TBI have a bidirectional relationship, each elevating risk for the other, but further research is necessary to understand the mechanisms of this interaction.

In light of this relationship, health care providers recognize a need to develop targeted treatment strategies to prevent the development of schizophrenia in TBI patients and to mitigate poor outcomes in TBI patients who have already have the condition. Schizophrenia symptoms can limit a patient’s ability to engage in TBI follow-up care, may be associated with other behaviors that can impede TBI recovery (such as substance use), and can increase the risk of sustaining a subsequent head injury. Clinicians should remain aware that TBI patients may need specialized monitoring and intervention for schizophrenia, especially those with a family history of the disorder.

Works Cited:

1. Jorge RE, Robinson RG, Moser D, et al. Major depression following traumatic brain injury. Archives of General Psychiatry. (2004).
2. Fann JR, Hart, T, & Schomer KG. Treatment for depression after traumatic brain injury: A systematic review. Journal of Neurotrauma. (2009).
3. The National Institute of Mental Health. Schizophrenia. (2021). Retrieved from: https://nimh.nih.gov/health/topics/schizophrenia.
4. Hilker R, Helenius D, Fagerlund B, et al. Heritability of schizophrenia and schizophrenia spectrum based on that Nationwide Danish Twin Register. Biological Psychiatry. (2018).
5. Molloy C, Conroy RM, Cotter DR, & Cannon M. Is traumatic brain injury a risk factor for schizophrenia? A meta-analysis of case-controlled population-based studies. Schizophrenia Bulletin. (2011).
6. Malaspina D, Goetz RR, Friedman JH, et al. Traumatic brain injury and schizophrenia in members of schizophrenia and bipolar pedigrees. American Journal of Psychiatry. (2001).
7. Schwarzbold M, Diaz A, Martins ET, et al. Psychiatric disorders and traumatic brain injury. Neuropsychiatric Disease and Treatment. (2008).

Our TBI Attorneys Will Advocate for You

Our lawyers at Scarlett Law Group are listed among the Best Lawyers in America and have been Included in California Super Lawyers list. Our firm was rated among the Top 100 Trial Lawyers® in the Country, and we are here to leverage our firm’s reputation and resources if you or a loved one sustained a moderate to severe brain injury.

In many cases of severe traumatic brain injuries, the individual is left unable to care for themselves or live independently, often requiring long-term care to help perform basic daily functions, such as feeding and cleaning themselves. The level of treatment that many severe traumatic brain injury victims require often amounts to hundreds of thousands of dollars in medical bills. The results of your personal injury lawsuit will have an important and long-term impact on your quality of life, so let us put our skills and knowledge of the law to work for you today.

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