This dissertation aimed to: (1) estimate the association between recurrent concussion and mental health; and (2) compare athlete-recalled and clinically-documented concussion histories during college. Questionnaires were completed by 797 former collegiate athletes who played collegiate sport between 1987-2012. Athlete-recalled concussions from 130 former collegiate athletes were individually linked to previously collected clinical data that tracked medically-diagnosed concussions at the host institution between 1996 and 2012. In Aim 1, binomial regression estimated adjusted prevalence ratios (PR), with depression, impulsivity, and aggression as outcomes. Controlling for alcohol dependence and family history of depression, the prevalence of currently meeting diagnostic criteria for major depression among former collegiate athletes reporting three of more concussions was 2.6 times that of those reporting no concussions [95% Confidence Interval (CI): 1.1, 6.1]. No association was found for impulsivity. Controlling for alcohol dependence, sex, and relationship status, former collegiate athletes reporting three or more concussions had a higher prevalence of high levels of aggression, compared to those reporting no concussions (PR=1.2; 95% CI: 1.0, 1.5). In Aim 2, intraclass correlation coefficients (ICC) assessed agreement between athlete-recalled and clinically-documented concussion histories. Descriptive analyses assessed reasons for disagreement. Agreement between athlete-recalled and clinically-documented concussion histories was low (ICC: 0.21; 95% CI: 0.05, 0.37), but higher for females (ICC=0.65; 95% CI: 0.44, 0.79) and those playing more recently (2005-2012: ICC=0.39; 95% CI: 0.01, 0.67). Of those sustaining college sports-related concussions (40.8%), 39.6% believed they had sustained concussions that went undiagnosed, and 20.8% admitted non-disclosure of suspected concussions. Common reasons for non-disclosure included: did not think injury was serious enough (90.9%); did not know it was a concussion (72.7%); and did not want to leave the game/practice (72.7%). In summary, former collegiate athletes reporting concussions may be at greater risk for major depression and higher levels of aggression. However, current sources of concussion history data apparently fail to capture large proportions of concussions. Methodological research is needed to improve the quality of concussion history assessment tools. The health and well-being of collegiate athletes should continue to be monitored even after transitioning out of collegiate sports.Doctor of Philosoph
