Concussion Increases Suicide Risk

Canadian research indicates that adults who experience a concussion appear to have a three times greater risk of suicide than the general population, with this risk increasing among those who experience their concussion during the weekend. The longitudinal cohort analysis of adults with a diagnosis of a concussion in Ontario, Canada, from April 1, 1992 to March 31, 2012 was published online ahead of print on February 8 in CMAJ (Canadian Medical Association Journal).

“Given the quick usual resolution of symptoms, physicians may underestimate the adverse effects of concussion and its relevance in a patient's history,” said senior author Donald Redelmeier, MD, MSHSR, FRCPC, FACP, senior core scientist at the Institute for Clinical Evaluative Sciences (ICES) and a physician at Sunnybrook Health Sciences Centre, Toronto, Ontario. “Greater attention to the long-term implications of a concussion might save lives because deaths from suicide can be prevented.”

Whereas head injuries have been associated in previous research with subsequent suicided among military personnel and professional athletes, little was known prior to the current study regarding outcomes following concussion among adults in the community. But with nearly 4,000 deaths from suicide in Canada and more than 38,000 in the United States in 2010; concussion recognized as the most common brain injury in adults; and about 400,000 cases of concussion in Canada and 4 million in the US each year, Redelmeier and colleagues sought to assess the long-term risk of suicide after concussions occurring on weekends or weekdays in the community. “The link between concussion and suicide is not confined to professional athletes or military veterans,” said co-author Michael Fralick, MD, a medical trainee at the University of Toronto.

For the study, the investigators assessed anonymized records for more than 235,000 patients with a concussion over a 20-year period in Ontario, based on diagnostic codes from the health insurance database. Participants had an average age of 41 years; 52% were men, 86% lived in an urban area, and most had no prior suicide attempt, hospitalization, or past psychiatric disorder.

Over a median follow-up of 9.3 years, a total of 667 subsequent suicides occurred, equivalent to 31 deaths per 100,000 patients annually, or three times the population norm. The average time from concussion to subsequent suicide was 5.7 years. Of the suicides, 519 occurred among patients diagnosed with a concussion on a weekday (29 suicides per 100,000 patients annually). Those diagnosed with a concussion on weekends accounted for 148 suicides (39 per 1000,000 patients annually.

The increased risk was seen regardless of patients’ demographics, was independent of past psychiatric conditions, became accentuated with time, and exceeded the risk observed among members of the military. Additional concussions further increased the risk of suicide. Perhaps most troubling is the finding that about one-half of patients had visited a physician in the last week of life, and majority having visited their family physician in the last month of life. The most common means of suicide was drug overdose, and the average age at suicide was 44 years.

“…no past study, to our knowledge, has focused on concussions and tested the potential difference between weekends and weekdays,” wrote the authors. “The increased long-term risk of suicide observed in this study persisted among those who had no psychiatric risk factors and was distinctly larger than among patients after an ankle sprain.”