Suicide after Concussion Rare, But Risk is Higher

Concussion and mild traumatic brain injury (TBI) were tied to an increased risk of suicide, a meta-analysis found.

Though suicide after concussion was rare, patients diagnosed with concussion or mild TBI had double the risk of suicide and a higher risk of suicide attempts and suicidal thoughts than people without brain injuries, reported Michael Fralick, MD, of the Harvard T. H. Chan School of Public Health of Boston and currently with the University of Toronto, and colleagues in JAMA Neurology.

"Over 99% of people who have a concussion do not experience a suicide-related event," Fralick told MedPage Today. "The majority of people feel better within 1 to 2 weeks of experiencing a concussion. For anyone who has symptoms that last longer than this, or for anyone who notices a low mood or suicidal thoughts, it's really important to seek medical attention."

The systematic review and meta-analysis examined studies of children and adults that quantified the risk of suicide, suicide attempt, or suicidal ideation after concussion and included both military and non-military personnel. The researchers assessed the results of 17 studies that encompassed more than 700,000 concussion patients and 6.2 million people who had not been diagnosed with concussion, using the I² test statistic to quantify statistical heterogeneity (I² values range from 0% to 100%, with higher values indicating greater heterogeneity).

Overall, concussion or mild TBI was associated with a two-fold higher risk of suicide (RR 2.03, 95% CI 1.47-2.80, I² 96%, P<0.001). Despite the high I² value, the researchers conducted a meta-analysis because five of the six included studies were of a similar design, used the same validated method of identifying both brain injury and suicide, and were of relatively high quality.

In two studies that provided estimates with a median follow-up of approximately 4 years, 1,664 of 333,118 individuals (0.50%) and 750 of 126,114 individuals (0.59%) diagnosed with concussion or mild TBI died by suicide. Studies with longer follow-up reported that 667 of 235,110 concussion patients (0.28%) died by suicide over a median of 9.3 years, and 26 of 5,314 people who had a concussion as a child (0.49%) died by suicide over a median of 12.3 years.

Most studies also reported a heightened risk of suicide attempt or suicidal ideation for people diagnosed with mild TBI compared with those not diagnosed. Increased risk of suicide outcomes after concussion emerged in studies with and without military personnel, the researchers noted.

This analysis suggests that links between concussions and suicide are "not isolated to elite professional athletes and may extend to ordinary people in everyday activities," noted Donald Redelmeier, MD, and Junaid Bhatti, MBBS, PhD, of the University of Toronto, in an accompanying editorial.

"The findings also argue that this risk may be even greater for adults in civilian fields than in military occupations," they wrote. "The data do not identify the time course of events yet imply a many-year lag between a concussion and subsequent suicide. The absolute risks are modest because most people do not die by suicide, although the increases might extend to other forms of mental illness that decrease quality of life."

The authors noted several limitations to their analysis. Most studies provided only relative risks; the researchers could not quantify an absolute number of excess cases of suicide attributable to concussion. They also could not quantify suicide risk on a per-injury basis. Most studies also were retrospective and most lacked an active comparator; causal associations cannot be inferred and unknown confounders may have influenced results.