Risk of suicide after a concussion

Fralick M, Thiruchelvam D, Tien HC, Redelmeier DA. Risk of suicide after a
concussion. CMAJ. 2016 Feb 8. pii: cmaj.150790. [Epub ahead of print]

Abstract

BACKGROUND:

Head injuries have been associated with subsequent suicide among military personnel, but outcomes after a concussion in the community are uncertain. We assessed the long-term risk of suicide after concussions occurring on weekends or weekdays in the community.

METHODS:

We performed a longitudinal cohort analysis of adults with diagnosis of a concussion in Ontario, Canada, from Apr. 1, 1992, to Mar. 31, 2012 (a 20-yr period), excluding severe cases that resulted in hospital admission. The primary outcome was the long-term risk of suicide after a weekend or weekday concussion.

RESULTS:

We identified 235,110 patients with a concussion. Their mean age was 41 years, 52% were men, and most (86%) lived in an urban location. A total of 667 subsequent suicides occurred over a median follow-up of 9.3 years, equivalent to 31 deaths per 100,000 patients annually or 3 times the population norm. Weekend concussions were associated with a one-third further increased risk of suicide compared with weekday concussions (relative risk 1.36, 95% confidence interval 1.14-1.64). The increased risk applied regardless of patients' demographic characteristics, was independent of past psychiatric conditions, became accentuated with time and exceeded the risk among military personnel. Half of these patients had visited a physician in the last week of life.

INTERPRETATION:

Adults with a diagnosis of concussion had an increased long-term risk of suicide, particularly after concussions on weekends. Greater attention to the long-term care of patients after a concussion in the community might save lives because deaths from suicide can be prevented.
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Now, new research published in the Canadian Medical Association Journal shows that even mild concussions sustained in ordinary community settings might be more detrimental than anyone anticipated; the long-term risk of suicide increases threefold in adults if they have experienced even one concussion. That risk increases by a third if the concussion is sustained on a weekend instead of a weekday—suggesting recreational concussions are riskier long-term than those sustained on the job. “The typical patient I see is a middle-aged adult, not an elite athlete,” says Donald Redelmeier, a senior scientist at the University of Toronto and one of the study’s lead authors. “And the usual circumstances for acquiring a concussion are not while playing football; it is when driving in traffic and getting into a crash, when missing a step and falling down a staircase, when getting overly ambitious about home repairs—the everyday activities of life.”...

For weekend concussions, the later suicide risk increased to four times the norm. Redelmeier and his fellow researchers had wondered whether the risk would differ between occupational and recreational concussions. They did not have information about how the concussions happened, so they used day of the week as a proxy. Although they do not know why weekend risk is indeed higher, they suspect it may be because on weekends medical staff may not be as available or accessible or people may not seek immediate care.

Although the underlying causes of the connection between concussion and suicide are not yet known, Redelmeier says that there were at least three potential explanations. A concussion may be a marker but not necessarily a mechanism of subsequent troubles—or, in other words, people who sustain concussions may already have baseline life imbalances that increase their risks for depression and suicide. “But we also looked at the subgroup of patients who had no past psychiatric history, no past problems, and we still found a significant increase in risk. So I don’t think that’s the entire story,” he notes. One of the more likely explanations, he says, is that concussion causes brain injury such as inflammation (as has been found in some studies) from which the patient may never fully recover. Indeed, a study conducted in 2014 found that sustaining a head injury leads to a greater risk of mental illness later in life. The other possibility is that some patients may not give themselves enough time to get better before returning to an ordinary schedule, leading to strain, frustration and disappointment—which, in turn, may result in depression and ultimately even suicide.

Lea Alhilali, a physician and researcher at the Barrow Neurological Institute who did not participate in this study, uses diffusion tensor imaging (an MRI technique) to measure the integrity of white matter in the brain. Her team has found similarities between white matter degeneration patterns in patients with concussion-related depression and noninjured patients with major depressive disorder—particularly in the nucleus accumbens, or the “reward center” of the brain. “It can be difficult to tease out what’s related to an injury and what’s related to the circumstances surrounding the trauma,” Alhilali says. “There could be PTSD, loss of job, orthopedic injuries that can all influence depression. But I do believe there’s probably an organic brain injury.”...

This new study may only represent the tip of the iceberg. “We’re only looking at the most extreme outcomes, at taking your own life,” Redelmeier says. “But for every person who dies from suicide, there are many others who attempt suicide, and hundreds more who think about it and thousands more who suffer from depression.”...

Redelmeier is adamant that people should take concussions seriously. “We need to do more research about prevention and recovery,” he says. “But let me at least articulate three things to do: One, give yourself permission to get some rest. Two, when you start to feel better, don’t try to come back with a vengeance. And three, even after you’re feeling better, after you’ve rested properly, don’t forget about it entirely. If you had an allergic reaction to penicillin 15 years ago, you’d want to mention that to your doctor and have it as a permanent part of your medical record. So, too, if you’ve had a concussion 15 years ago.”

http://www.scientificamerican.com/article/a-single-concussion-may-triple-the-long-term-risk-of-suicide1/?WT.mc_id=SA_MB_20160210