Findings provide insight into TBI-suicide link
Risk of suicide was doubled in persons who experienced a concussion or mild traumatic brain injury (TBI) earlier in life, according to results of a meta-analysis of 17 studies representing nearly 7 million patients.
However, the absolute risk of suicide remained quite low, according to Michael Fralick, MD, of the University of Toronto, and co-investigators.
“Nearly all patients diagnosed with concussion and/or mild TBI did not die by suicide,” Dr. Fralick and colleagues said in their report on the study, which appears in JAMA Neurology.
Nevertheless, the meta-analysis illustrates evidence for an increased risk of suicide, suicide attempts, and suicidal ideation for persons with a history of these injuries, they said in the report.
The meta-analysis included 10 cohort studies, 5 cross-sectional studies, and 2 case-control studies looking at the risk of suicide, suicide attempts, or suicidal ideation after a concussion or mild TBI. Those studies included a roughly 714,000 individuals with a concussion and/or TBI diagnosis, and 6,236,000 without a diagnosis.
For people diagnosed with at least one concussion and/or mild TBI, the risk of suicide was 2-fold higher (relative risk, 2.03; 95% CI, 1.47-2.80; P less than 0.001), according to the report.
The risk was “slightly stronger,” investigators said, when the analysis was limited to studies adjusting for factors associated with those brain injuries and with suicide (RR, 2.10; 95% CI, 1.40-3.13; P less than 0.01).
Four of the 5 cohort studies reported absolute risk of suicide, according to Dr. Fralick and coauthors. In one study with a median follow-up of 3.6 years, 0.50% of individuals with a concussion and/or TBI subsequently died of suicide, while similarly, 0.59% died in a study with 4.0 years of follow-up, 0.28% in a study with 9.3 years follow-up, and 0.49% in one with a 12.3 year median follow-up.
Most of the studies in the meta-analysis reported an increased risk of suicide attempt after concussion and/or mild TBI, according to Dr. Fralick and his collaborators, while the eight studies looking at suicidal ideation all reported heightened risk after those brain injuries.
The researchers acknowledged some limitations of their analysis. Recall bias could have led to an overestimation of the association between concussion and suicide risk, since suicide attempts may affect reporting of concussion history, they said.
Furthermore, most of the studies were retrospective, and did not include an active comparator group, such as individuals with non-neurologic injuries, they added.
“Until large prospective studies with sufficiently large durations of follow-up are available, we have to rely on the currently available data,” they said in the report.
Dr. Fralick and co-authors reported no conflict of interest disclosures related to the study.
SOURCE: Fralick M, et al. JAMA Neurol. 2018 Nov 12.