Physical problems such as body pain are a key pathway between sport-related concussions and depression, according to a study published in the Journal of Neuropsychiatry and Clinical Neurosciences. The research, which examined retired NFL athletes, found there was no connection between concussion history and depressive symptoms among those without physical symptoms.

“Our interest arose from the amount and type of media coverage focusing on the mental health of retired NFL athletes and possible mood symptoms often attributed to chronic traumatic encephalopathy,” study authors Scott L. Zuckerman, the co-director for research at the Vanderbilt Sports Concussion Center, and Benjamin Brett, a postdoctoral research fellow the Medical College of Wisconsin, told PsyPost.

“While it often gets portrayed that sustaining sport-related concussions while playing contact sports at any level will increase the risk of future mental health problems in former athletes, clinicians who are in the field treating these individuals know that it is a much more complex process and the source of psychiatric symptoms can be multifaceted.”

“In other words, not all former athletes who sustained a sport-related concussion (or multiple) will inevitably develop mood symptoms, such as depression, later in life and other factors likely play a role in this process. In that light, we wanted to further investigate the relationship between the number of self-reported concussions and depression symptoms in former NFL athletes, examining additional factors (i.e., somatic or physical symptoms) that may have an influence or moderate this relationship.”

The researchers had 43 former NFL athletes complete a battery of surveys, which were designed to measure clinical depression and somatic symptoms such as pain, dizziness and shortness of breath. The researchers also obtained a detailed head injury and concussion history from every participant.

The players reported an average of 8.7 sport-related concussions. Concussions and depressive symptoms were significantly moderated by somatic symptoms. In other words, former NFL players with more concussions tended to report more somatic symptoms, which in turn was associated with depression.

“We hope the average person takes away that the discussion of whether participation in contact sports can lead to later-life mental health and neurocognitive problems is complex, with many more questions than answers,” Zuckerman and Brett said.

“As our paper showed, the association between concussion history and depression, which is often portrayed as a causal relationship, was influenced by additional factors. In reality, the amount of bodily or somatic complaints had a larger effect than the number of concussions sustained by former NFL athletes.”

“Further, the amount of bodily or somatic symptoms endorsed moderated the relationship between sport-related concussion history (number of concussions) and depressive symptoms. If you had minimal to no bodily/physical symptoms, there was virtually no relationship between the number concussions that an individual sustained while playing contact sports and depression symptoms later in life. The more bodily/physical symptoms were endorsed, the stronger the association between self-reported concussion history and depression symptoms.”

The study — like all research — includes some limitations. Future research on the topic could benefit from larger, more diverse samples of participants.

“Many, many questions still exist. This study was in NFL athletes, which represent a miniscule percentage of the population. The more important public health questions are if these results apply to college, high school, or youth football players. We cannot answer those questions from this paper,” Zuckerman and Brett explained.

“Though most of the high-profile, headline-grabbing research is on elite, professional, and often NFL athletes, this is a drastically different population than the sons and daughters, who will play at most 4-years of contact sports in high school, and a select few will play in college. Additionally, we need to continue to identify other factors that influence mood and other psychiatric symptoms in former athletes at all levels.”

“There is greater accumulating evidence that participation in contact sports and/or a history of concussion does not alone inevitably result in psychiatric symptoms, and that other factors, such as athletes’ transition from sport to retirement as positive or negative, health status, quality of life, and their social support all play a role on the development of mental-health difficulties later in life,” Zuckerman and Brett added.

The study, “The Relationship Between Prior Concussions and Depression Is Modified by Somatic Symptomatology in Retired NFL Athletes“, was authored by Benjamin L. Brett, Nishit Mummareddy, Andrew W. Kuhn, Aaron M. Yengo-Kahn, and Scott L. Zuckerman.