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Traumatic brain injury increases risk for suicide

Patients who had traumatic brain injury and initiated medical contact were at higher risk for suicide than those without TBI, according to findings recently published in JAMA.

“Most previous studies examining the relation of TBI and completed suicide have been limited by methodological shortcomings, such as small sample sizes, in particular very low numbers of suicide cases with TBI,” Trine Madsen, PhD, of the Danish Research Institute of Suicide Prevention at the Mental Health Centre Copenhagen in the Capital Region of Denmark and colleagues wrote.

“These factors have compromised more detailed analyses, for instance with respect to severity, timely relation, and control of confounding variables,” they continued.

Researchers conducted a retrospective cohort study using nationwide registers

involving 7,418,391 individuals living in Denmark between 1980 and 2014, looking at 164,265,624 person-years’ follow-up.

Madsen and colleagues found 567,823 of the patients had a medical contact for TBI. These patients, when compared with the general population, had an associated risk for suicide with an incident rate ratio of 3.67 (95% CI, 3.33-4.04) within the first 6 months of the TBI and an IRR of 1.76 (95% CI, 1.67-1.86) for suicide 7 years after the TBI. Of the 34,529 individuals who died of suicide, 2,701 had mild TBI, 661 had severe TBI, and 174 had skull fracture without documented TBI.

Researchers also found that the absolute suicide rate was 41 per 100,000 person-years (95% CI, 39.2-41.9) in patients with TBI compared with 20 per 100,000 person-years (95% CI, 19.7-20.1) in those who did not have TBI. Additional analyses showed suicide risk was higher in patients who had severe TBI, prolonged hospital stays and many medical contacts.

“Traumatic brain injury is a major public health problem that has many serious consequences, including suicide,” Madsen and colleagues wrote. “The high prevalence of TBI globally emphasizes the importance for preventing TBI in order to ameliorate its sequelae, such as increased suicide risk, which can be prevented resulting in saved lives. Falls or road traffic accidents account for the largest share of TBIs. Helmet use has a protective effect, especially falls related to bicycling and falls that occur at work.”

These findings confirm previous research, Lee Goldstein, MD, PhD, of the department of psychiatry at the Boston University School of Medicine, and Ramon Diaz-Arrastia, MD, PhD, of the department of neurology at the University of Pennsylvania Perelman School of Medicine wrote in a related editorial, adding that attention needs to shift to understanding why the link exists.

“Among the main questions stimulated by this research is the mechanism. How exactly do TBIs increase suicide risk? What are the substrates and processes that causally link TBI, a highly heterogeneous condition, to a singular catastrophic outcome? The answers are undoubtedly multifactorial and complex,” they wrote.

“Results [of previous animal studies] have led clinical researchers to postulate specific TBI endophenotypes that define different pathophysiologies and risk factor profiles. Much work is still to be done, but some of the key issues that require evaluation are becoming clear,” they added.

Until those issues are resolved, Goldstein and Diaz-Arrastia said clinicians should keep Madsen and colleagues’ findings in mind when treating patients with TBI. – by Janel Miller

Disclosure: The authors report no relevant financial disclosures.