Introduction: Prior research has demonstrated a positive relationship between sport-related concussion (SRC) history and increased depressive symptoms in retired National Football League (NFL) athletes. In this study, we aimed to determine whether somatic symptom endorsement influences the relationship between SRC history and self-reported depressive symptoms in retired NFL athletes.

Methods: Prior to this study, forty-three former NFL athletes prospectively completed multiple interviews and self-report inventories of depression (BDI-II) and somatic symptoms (PHQ-15). The current study was a retrospective analysis of the previously collected cross-sectional data. A moderation analysis examined the influence of somatic symptom endorsement on the relationship between SRC history and self-reported depressive symptom severity.

Results: Among 43 retired NFL athletes, average BDI-II score was 9.26 (8.95), and average PHQ-15 score was 5.35 (3.58). SRC history (b=0.28) and somatic symptom scores (b=0.53) accounted for a significant amount of depressive symptomatology, R^2 = 0.47, F(2,40), p < 0.001. The interaction of SRC history and somatic symptom endorsement explained a significant increase of variance in depressive symptom severity, delta R^2 = 0.05, F(1,39) = 5.05, p = 0.03. SRC history was not significantly associated with depressive symptom severity at low levels of somatic symptom endorsement (1SD below mean), p = 0.90. The relationship between SRC history and depression symptom severity was significant at mean (PHQ-15 = 5) and high (1 SD above mean) levels of somatic symptoms, p = 0.03 and p = 0.01, respectively (Figure 1).

Conclusions: In this cohort, the relationship between SRC history and self-reported depressive symptoms was significantly moderated by somatic symptom endorsement. The effect of somatic symptoms on depressive symptoms was nearly twice that of SRC history. These results suggest that the relationship between SRC and depression is complex, nuanced, and largely affected by somatic symptoms.

Patient Care: The current study can improve our understanding of how concussion and contact sports affect long-term neurologic function in former professional athletes.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of somatic symptomatology in the relationship between depression and concussion history in former professional football players. 2) Understand the complex and nuanced relationship between concussions and neuropsychological outcomes in retired athletes, and several modifying factors must be accounted for when studying neurologic outcomes in retired athletes.

References: 1. Kerr ZY, Marshall SW, Harding HP, Guskiewicz KM. Nine-year risk of depression diagnosis increases with increasing self-reported concussions in retired professional football players. Am J Sports Med. 2012;40(10):2206-2212. 2. Guskiewicz KM, Marshall SW, Bailes J, et al. Recurrent concussion and risk of depression in retired professional football players. Med Sci Sports Exerc. 2007;39(6):903-909. 3. Didehbani N, Munro Cullum C, Mansinghani S, Conover H, Hart J. Depressive symptoms and concussions in aging retired NFL players. Arch Clin Neuropsychol. 2013;28(5):418-424.