There is societal concern that playing football might be associated with an increased risk for depression, suicidality, and suicide later in life. This concern has been fueled by intense media coverage of some current and former National Football League (NFL) players who have completed suicide. Over the past 100 years, a small number of current and former professional football players have died by suicide, and a disproportionate number of those deaths have occurred in recent years, since 2009.1 Specifically, the number of completed suicides between 1920 and 2008 (89 years) was 15 compared to 11 between 2009 and 2015 (7 years).1 Most of these men experienced significant life stressors before their deaths, such as retirement from sport, loss of steady income, divorce, failed business ventures, and estrangement from family members, in addition to medical, psychiatric, and/or substance abuse problems.1 This is consistent with a Centers for Disease Control and Prevention (CDC) report indicating that common precipitating events for suicide for people in the general population are depression, a life crisis, intimate partner problems, occupational or financial problems, criminal or legal proceedings, and physical health problems.2 That said, it is important to appreciate that former NFL players are at a statistically significantly lower risk, not a greater risk, for death by suicide than men from the general population.3,4
The authors, in their clinical practices, have provided care to adolescent and young adult athletes and retired professional athletes, who have expressed concerns about developing a brain disease and committing suicide. Some of these athletes have referred, specifically, to a concern about chronic traumatic encephalopathy (CTE), whereas others have not referred to CTE by name. Approximately 10 years ago, 2 research groups began to speculate, and assert, that suicide is a clinical feature of CTE in case series and review articles,5–11 and there was extensive media coverage of these claims before, during, and after those articles were published. Between 1928 and 2009, however, suicidal ideation and suicide were not considered to be clinical features of CTE.12–14 Suicidality and suicide were introduced as clinical features in the published literature, in 2010, by Omalu et al,15 and after 2010, researchers from Boston University and Omalu et al repeatedly asserted that suicidality and suicide are common clinical features of CTE.5–11 These researchers, however, cited limited or no studies to support this opinion because there were no published studies on this topic. In the introduction to their large case series published in 2013,5 McKee et al reported that CTE was associated with “heightened suicidality” citing their 2009 review article12 as the only source for that speculation; but, that review article did not conclude that suicidality or suicide were clinical features.12 Authors from other research groups have written review articles on this topic and concluded that the scientific evidence to support the assertion that suicide is a clinical feature of CTE is lacking and inconclusive.16–20 Although there is an absence of scientific evidence that suggests suicide is a clinical feature of CTE, that does not mean, of course, that some current and former athletes do not suffer from depression and experience suicidality.
Survey studies reveal that some former collegiate21,22 and professional23–25 football players experience problems with depression. A substantial number of former football players experience chronic pain,26 and those with depression and chronic pain also have greater life stress and financial difficulties.24 In the general population, depression27 and chronic pain28 are risk factors for suicidality, as are relationship problems29 and substance abuse.30,31 Therefore, it stands to reason that some former amateur and professional football players will experience suicidality at some point in their lives.
The National Longitudinal Study of Adolescent to Adult Health (Add Health) is a prospective cohort study following participants through 4 waves of survey data collection (eg, demographics, lifestyle, health, and mental health information), from 1994 to 2008, from adolescence through their late 20s.32,33 Two recent studies34,35 have used the Add Health survey data to examine the association between playing high school football and risk for mental health problems in early adulthood, approximately 15 years later. These studies illustrated that playing football in high school was not associated with greater mental health problems, including lifetime rates of depression,34,35 current symptoms of depression (ie, within the past 7 days35), lifetime rates of anxiety,35 lifetime rates of posttraumatic stress disorder,35 suicidal ideation within the past year,34,35 and substance abuse (ie, nicotine, cannabis, and alcohol35).
This study, using a different methodological approach, sought to replicate and extend previous findings regarding adolescent football participation and suicidality in early adulthood. Specifically, we examined suicidality at the following 3 time points: during adolescence, early 20s, and late 20s. We identified possible risk factors for suicidality during adolescence and examined them as predictors for suicidality during early adulthood. We hypothesized that playing football during adolescence would be unrelated to depression and suicidality in early adulthood, but having mental health difficulties during adolescence, especially suicidality, would be an important predictor of experiencing suicidality in early adulthood.
This study used pre-existing, public-use data collected through the Add Health study.36 The Add Health study is a longitudinal study of nationally representative individuals that was started during the 1994 to 1995 school year when the participants were adolescents (ie, grades 7-12; wave I). Eighty high schools and 52 middle schools were selected using systematic sampling methods and implicit stratification to ensure the sample was representative of US schools regarding region, size, type, ethnicity, and urbanicity. There were 20 745 youths who completed the full Add Health study at wave I. In the public use version of the database that was used in this specific study, wave I data are only available for 6504 participants. Some of these individuals completed follow-up interviews in 1996 (wave II, n = 4834), 2001 to 2002 (wave III, ages 18-26, n = 4882), and most recently in 2008 when the participants were approximately 24- to 32-years-old (wave IV, n = 5114).32 Separate databases from waves I, III, and IV were merged using participant identification numbers so that data could be examined longitudinally. From this database, participants were included in this study if they were boys in the wave I database (n = 3147) and had viable data at wave IV related to our primary outcomes (ie, a lifetime history of a diagnosis of depression and suicide ideation in the past year; n = 2353).
At wave I, we extracted data related to football participation [question S44A21; “Are you participating/Do you plan to participate in the following clubs, organizations, and teams (check all that apply): football”]. Importantly, it is not possible to determine, with certainty, whether all the boys actually played football. We also extracted data related to mental health, such as a history of psychological treatment (wave I question H1HS3, “In the past year, have you received psychological or emotional counseling?”), suicide ideation (wave I question H1SU1, wave III question H3TO130, and wave IV question H4SE1 “During the past 12 months, did you ever seriously think about committing suicide?”), suicide attempts (wave I question H1SU2, “During the past 12 months, how many times did you actually attempt suicide?”), a lifetime history of a depression diagnosis (wave IV, question H4ID5H, “Has a doctor, nurse, or other healthcare providers ever told you that you have or had: depression?”), and depressed mood (wave IV, question H4MH22 “How often was the following true during the past 7 days? You felt depressed;” response options: never or rarely, sometimes, a lot of the time, most of the time, or all the time).
Descriptive statistics were used to summarize the sample. Chi-squared analyses were used to determine if the proportion of the participants who had mental health difficulties in waves III and IV was different based on football participation at wave I. Chi-squared analyses were also used to examine whether rates of mental health difficulties during wave IV were associated with mental health difficulties in adolescence (ie, undergoing psychological counseling, suicide ideation, and suicide attempts at wave I), suicide ideation at wave III, and co-occurring mental health difficulties at wave IV. For all analyses, SPSS version 24.0 was used. The threshold for statistical significance was P < 0.05.
Data Availability Statement
The data used in this study are publicly available. Information on how to obtain the Add Health data files is available on the Add Health Web site (http://www.cpc.unc.edu/addhealth).
Description of the Sample
There were 3147 boys who participated in this study during adolescence and were included in the wave I database. Of those, 2353 (74.8%) were interviewed approximately 15 years later, during wave IV of this longitudinal study. Men were selected for this study if they completed the wave IV interview and answered the questions relating to a lifetime history of a diagnosis of depression and whether they have experienced suicide ideation in the past year. The interviews were conducted in 2007 (1%), 2008 (98%), and 2009 (1%). The cohort included 2318 men with a mean age of 29.1 years [median (Md) = 15, SD = 1.8, interquartile range (IQR) = 28-31, range = 25-34]. During adolescence, they were interviewed at a mean age of 14.9 years (Md = 15, SD = 1.8, IQR = 14-16, range = 11-19). The breakdown of the cohort by race was as follows: White = 69.5%, African American = 21.8%, Native American = 1.0%, Asian/Pacific Islander = 3.4%, and others or missing = 4.4%. Their highest level of education at the time of the wave IV interview was as follows: eighth grade or less = 0.3%, some high school = 8.9%, high school graduate = 20.3%, some vocational/technical training = 4.3%, completed vocational/technical training = 5.9%, some college = 32.3%, bachelor's degree = 18.1%, some graduate school = 3.4%, master's degree = 3.4%, some graduate school beyond a master's degree = 0.7%, and doctoral degree or other postbaccalaureate professional education = 2.4%. Of this cohort, 1856 (80.1% of 2318) of the men completed interviews during wave III, and these interviews were conducted during 2001 (71.7%) and 2002 (28.3%). At that time, the mean age of the participants was 21.9 years (Md = 22, SD = 1.8, IQR = 20-23, range = 18-27).
Football in High School and Suicide Ideation During Early Adulthood
During the wave IV interview, 229 men (9.9%) reported a lifetime history of being diagnosed with depression, 131 (5.7%) reported having suicide ideation over the past year (Figure 1), and 109 (4.7%) reported feeling depressed in the past 7 days. During wave IV, of the total sample, 73.3% (1699) answered the question, during adolescence, about playing football, with 473 (27.8%) answering affirmatively. Those men who reported playing football (or the intention to play football), compared with those who did not, reported similar rates of lifetime diagnosis of depression [7.6% vs 10.3%; χ2(1) = 2.813, P = 0.093, odds ratio (OR) = 0.719, 95% confidence interval (CI) = 0.489-1.059], suicide ideation in the past year [5.1% vs 5.9%; χ2(1) = 0.408, P = 0.523, OR = 0.857, 95% CI = 0.533-1.377], and feeling depressed in the past 7 days [3.8% vs 4.2%; χ2(1) = 0.110, P = 0.740, OR = 0.911, 95% CI = 0.527-1.577]. During wave III, when the participants were in their early 20s, those men who reported playing football, compared with those who did not, reported similar rates of suicide ideation in the past year [6.3% vs 6.3%; χ2(1) = 0.005, P = 0.946, OR = 0.983, 95% CI = 0.603-1.603].
Mental Health in Adolescence and Suicidality in Young Adulthood (Wave IV)
During the initial interview, there were 259 boys (10.9%) who reported undergoing psychological counseling in the past year while in high school. During the wave IV interview, approximately 15 years later, those individuals who underwent psychological counseling during adolescence were much more likely to report a lifetime history of depression [20.2% vs 8.6%, χ2(1) = 34.000, P < 0.001, OR = 2.689, 95% CI = 1.907-3.791] and suicide ideation in the past year [11.1% vs 5.0%, χ2(1) = 15.563, P < 0.001, OR = 2.367, 95% CI = 1.524-3.675] but not current depression [7.1% vs 4.4%, χ2(1) = 3.665, P = 0.56, OR = 1.659, 95% CI = 0.983-2.800], compared with those who did not.
When interviewed during adolescence, 236 boys (10.2%) endorsed thoughts of suicide in the past year, and 51 (2.2%) reported attempting suicide in the past year. At the follow-up assessment, approximately 15 years later, those men who reported suicidality during adolescence, compared with those who did not, were much more likely to report a lifetime history of depression [21.2% vs 8.5%; χ2(1) = 38.305, P < 0.001, OR = 2.884, 95% CI = 2.035-4.085], suicide ideation in the past year [17.4% vs 4.3%; χ2(1) = 68.748, P < 0.001, OR = 4.721, 95% CI = 3.169-7.034], and feeling depressed within the past 7 days [7.2% vs 4.3%; χ2(1) = 4.027, P = 0.045, OR = 1.723, 95% CI = 1.007-2.948]. Those men who attempted suicide during adolescence, compared with those who did not, were much more likely to report a lifetime history of depression [33.3% vs 8.6%; χ2(1) = 36.501, P < 0.001, OR = 5.136, 95% CI = 2.911-9.705], suicide ideation in the past year [27.5% vs 4.3%; χ2(1) = 57.413, P < 0.001, OR = 8.375, 95% CI = 4.371-16.046], and feeling depressed within the past 7 days [13.7% vs 4.4%; χ2(1) = 9.742, P = 0.002, OR = 3.441, 95% CI = 1.509-7.848].
Suicide Ideation During Wave III and Wave IV
During wave III, 1801 men answered the question about suicide ideation in the past year and 4.9% answered affirmatively. Those who endorsed suicide ideation during wave III, compared with those who did not, reported much higher rates of suicide ideation in the past year during wave IV [21.1% vs 4.4%; χ2(1) = 56.691, P < 0.001, OR = 5.732, 95% CI = 3.455-9.510].
Current Depression and Suicidality
During the wave IV interview, 109 (4.7%) men reported that they felt depressed either “a lot of the time” or “most of the time or all of the time” over the past 7 days. Those men who felt depressed in the past 7 days, compared with those who did not, were much more likely to endorse suicidality in the past year [36.7% vs 4.1%; χ2(1) = 206.756, P < 0.001, OR = 13.493, 95% CI = 8.669-21.001].
This large-scale longitudinal study illustrates that self-reported participation in high school football is not associated with an increased risk for depression or suicidality in early adulthood. Those men who reported playing football (or the intention to play football, during adolescence), compared with those who did not, reported similar rates of suicide ideation in the past year during both their early 20s (wave III interview) and their late 20s (wave IV interview). Their mental health in their late 20s was associated with their mental health during adolescence. Specifically, those boys who underwent psychological counseling during adolescence were more likely to report suicide ideation during their late 20s, and those who had thoughts of suicide during adolescence were much more likely to report suicide ideation and feeling depressed in their late 20s. Boys who attempted suicide during adolescence were at particularly a high risk for suicide ideation during their late 20s. Moreover, experiencing suicide ideation during one's early 20s was strongly associated with experiencing suicide ideation in one's late 20s. Finally, those men who felt depressed during their late 20s, at the time they were interviewed, reported a fairly high rate of suicide ideation in the past year.
Two previous studies using this Add Health longitudinal database came to the same conclusion that playing high school football is not associated with an increased risk for depression or suicidality approximately 15 years later, during early adulthood.34,35 Moreover, researchers using data from the Wisconsin Longitudinal Study reported that playing high school football was not associated with cognitive problems or depression in men later in life, at approximately age 65 years.37 This study replicated the previous findings34,35 between playing (or intending to play) high school football and a lifetime diagnosis of depression, current depressive symptoms, and suicide ideation at wave IV using a different analytical strategy and expanded those analyses by examining the association between adolescent football participation and suicide ideation at wave III. Furthermore, we broadened the scope by examining the association between mental health difficulties during adolescence and suicidality both during adolescence and approximately 5 years later during their early 20s (wave III) and approximately 10 years later during their late 20s (wave IV). We found strong associations between mental health and suicidality in adolescence and suicidality during early adulthood.
Factors Relating to Suicidality
During adolescence, a high level of physical activity and participation in team sports are associated with higher self-esteem and life satisfaction and a lower risk for psychological distress.38–41 Involvement in school sports during adolescence is associated with better mental health in young adulthood,42 and adolescents who are physically active in general, and maintain that behavior into early adulthood, experience better mental health.43 By contrast, parental psychological distress44 and marital problems45,46 are risk factors for mental health difficulties in adolescents. In addition, academic problems47 and being bullied47,48 at school are risk factors for psychological distress,47 including suicide ideation and attempts,48,49 in adolescents. Childhood sexual abuse, physical abuse, emotional abuse, and neglect are all associated with suicidal ideation and attempts in adolescents and young adults, and some studies suggest that sexual abuse and emotional abuse may be relatively more important than other forms of abuse and neglect.50–53 In college students, depression, cumulative stressful life events, sleep difficulties, a disconnection from others, and a sense of hopelessness are associated with a heightened suicide risk.54 In men, factors associated with violent suicides and suicide attempts include overconsumption of alcohol or drugs and suicide attempts in the biological family.55 High-risk patterns of thinking include hopelessness;56,57 problem-solving deficits, such as difficulty conceptualizing adaptive solutions to life problems;58 perceived burdensomeness and thwarted belongingness (a belief that one does not have meaningful interpersonal relationships);59 and mental pain (perception of strong negative feelings and changes in one's sense of self and functioning).60 A CDC report examining suicides identified common precipitating events as depression, a life crisis, intimate partner problems, physical health problems, occupational or financial problems, and criminal or legal proceedings.2
This study has 5 important methodological limitations. First, inclusion into the football group was based on responses to “Are you participating/Do you plan to participate in the following clubs, organizations, and teams (check all that apply): football.” As such, there is the potential that some participants included in this group intended to but ultimately did not play football. There is no way of knowing how many did not play the sport. Thus, this group presumably contained boys who were starters, who made the team but did not play often in games, and boys who intended to play but either did not try out, did not get selected, or who quit part way through the season. Second, these data did not assess duration of football career or number of concussions sustained; thus limiting our ability to assess a so-called dose–response relationship between these exposure variables and future mental health concerns. Third, this study purposefully examined football participation, which precludes generalizing these findings to other contact sports (eg, ice hockey, rugby, and soccer) or to women. Future research may wish to examine for sex and sport-based effects in these variables of interest. Fourth, all information was derived from self-report data and thus subject to reporting biases. Finally, the period in which these data were collected is important to consider. The wave IV data for this longitudinal study were collected before the modern CTE era. In recent years, the general public, and athletes in particular, have been inundated with information, and misinformation, relating to suicide and CTE. It is not known whether a similar survey conducted now would yield the same results.
In conclusion, this study illustrates that young men who reported that they played high school football are not at an increased risk for suicide ideation during their early or late 20s. By contrast, those who experienced mental health problems and suicidality during adolescence were much more likely to experience suicide ideation during their 20s, consistent with previous studies.61–64 Some former high school, collegiate, and professional football players will experience depression and suicidality at some point or points during their adult lives. It is overly simplistic, and inconsistent with the published literature, to link suicidality with playing high school football. The underlying causes for suicidality are usually complex and multifactorial. When these mental health problems arise in former athletes, it is important to provide them with high quality evidence-informed mental health care.
This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Information on how to obtain the Add Health data files is available on the Add Health Web site (http://www.cpc.unc.edu/addhealth). No direct support was received from grant P01-HD31921 for this analysis.
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