Examining Suicidality in Adolescents Who Have Sustained Concussions

Abstract

Previous studies have reported an association between concussion and suicidality in high school students in the United States. When controlling for multiple life stressors in adolescence (e.g., bullying, substance use, poor grades), however, the relationship between concussion and suicidality was either attenuated or became non-significant in one study. Rather than assessing concussion as a possible risk factor for suicidality, this study examined predictors of ideation, planning, and attempts among youth who experienced concussion in the past year. The sample included 13,677 participants from the 2019 Youth Behavior Risk Survey, of whom 1754 (13%) reported experiencing a concussion in the past year. Binary logistic regressions were conducted to predict ideation, planning, and attempts with modifiable stress factors, including physical activity, bullying, poor grades, insufficient sleep, binge drinking, marijuana use, illicit drug use, and depression. Among adolescents who experienced a concussion in the past year, 25% reported suicidal ideation (31% girls/19% boys), 20% reported suicide planning (25% girls/17% boys), and 15% reported a suicide attempt (17% girls/13% boys). In a multi-variable model among girls with prior year concussion, being bullied (odds ratio [OR] = 2.37), illicit drug use (OR = 2.80), current marijuana use (OR = 2.47), and depression (OR = 9.22) predicted suicidal ideation. Among boys with prior year concussion, being bullied (OR = 2.29) and depression (OR = 9.50) predicted suicidal ideation. Additional models were used to examine the association between having one or more modifiable stressors and suicidality, revealing that having three or more modifiable stressors was associated with a substantial increase in proportions of youth reporting suicidality. Among adolescents experiencing a concussion, treating depression and substance use, stopping bullying, and increasing physical activity may be associated with reduced risk for suicidality.

Introduction

Suicide is the second leading cause of death in adolescents in the United States.¹ A national survey study in 2019 revealed that 13.3% of high school boys and 24.1% of high school girls experienced suicide ideation during the past year.² Every two years, the Centers for Disease Control and Prevention (CDC) in the United States conducts a national survey of high school students called the Youth Risk Behavior Survey (YRBS).³ Using epidemiological data from the YRBS, researchers have found an association between sustaining a concussion, mostly during sports or recreational activities, and suicidality in high school students^4

–8—even after controlling for depression⁵ and bullying.^4,6

A recent study, however, analyzing the 2019 YRBS data, found that after controlling for a broader range of variables, the associations between concussion and suicidality were greatly attenuated or became nonsignificant.⁹ For high school girls, there were no statistically significant associations in the multi-variable analyses between concussion and suicidal thoughts, plans, or attempts. For high school boys, there were no statistically significant associations in the multi-variable analyses between concussion and suicidal thoughts or plans, but there was an association between concussion and suicide attempts.

Over the years, researchers using data from the YRBS have reported that suicidality in adolescents is associated with (1) psychosocial adversity, such as adverse childhood experiences,^10,11 physical teen dating violence,¹² forced sexual intercourse,^13,14 bullying,^13,15
–17 and cyberbullying^13,15

–18; (2) substance use, such as alcohol use,^13,19
–21 marijuana use,^19,22,23 illicit drug use,^13,23 and prescription opioid misuse^24–3426; (3) body weight perceptions, both underweight¹⁶ and overweight^16,27; (4) excessive television/video game/internet use^28,29; and (5) insufficient sleep.³⁰ Therefore, it is difficult to determine whether, or the extent to which, concussion is truly an independent risk factor for suicidality at the population level, and certainly at the individual level, because injured youth might also experience several other risk factors.

That said, a subgroup of children and adolescents who sustain a concussion will experience significant mental health problems. For example, youth presenting to specialty clinics for treatment and rehabilitation after concussion often experience difficulties with anxiety and depression.^31,32 Moreover, youth who have pre-injury mental health problems are more likely to experience post-injury anxiety and depression^31,33—both of which are risk factors for suicidality. Without question, more focused research is needed to better understand risk factors for suicidality in adolescents who have experienced a concussion. This work is essential for improving identification of youth at risk and informing medical management and psychological treatment.

Purpose of the present study

The purpose of this study is to examine the associations between a broad range of risk factors and suicidality in high school boys and girls who have sustained a concussion. All previous studies using the YRBS have focused on determining whether, or not, concussion was associated with, or a risk factor for, suicidality. Our approach is fundamentally different in that we will focus on studying youth who have sustained a concussion, which aligns with, and is relevant to, the normal medical management provided by athletic trainers, school nurses, pediatricians, and other healthcare providers—that is, we focus on risk factors associated with suicidality, particularly modifiable risk factors, in youth who have sustained a concussion within the past year.

First, we will examine single variable and multiple variable associations between a range of risk factors and suicidality in girls and boys who have sustained a concussion in the past year. Second, we will create a “stress index” comprising potentially modifiable risk factors and examine the association between that index and suicidality. We hypothesize that cumulative stressors are associated with greater risk for all aspects of suicidality in both girls and boys.

Methods

Sample

The CDC sponsors a national survey, of students in grades 9–12 every two years. Students from public and private schools across the United States are included. The survey is voluntary, anonymous, and is completed during a single class period (approximately 45 min). The CDC Institutional Review Board approved the protocol for the survey. During 2019, the total national sample included 13,872 students from 136 schools.³ The response rate for the students was 80.3% and for the schools was 75.1%, yielding an overall response rate of 60.3% (i.e., [student response rate] × [school response rate]).

A survey was deemed to fail quality control if fewer than 20 responses remained after review, or if the student marked the same answer for 15 or more consecutive questions. Applying such, 195 questionnaires failed quality control. The survey data used in this study, from 2019, are publicly available.³⁴

The database includes 13,677 subjects. Of those, 11,549 answered the question relating to whether they had experienced a concussion in the past year. Of those, 1754 (15.2%) responded yes. Of that group, 1715 responded to the question assessing for suicidal ideation. Sixteen were age 13 or younger, and 17 had missing data for age or sex and were excluded. The final sample included 1683 students—753 girls (44.7%) and 930 boys (55.3%). Age was distributed across the sample as follows: 14 (n = 200, 11.9%), 15 (n = 424, 25.2%), 16 (n = 469, 27.9%), 17 (n = 372, 22.1%), and 18 or older (n = 218, 13.0%).

Self-identified race and ethnicity was as follows: (1) 47.8% White, (2) 16.4% multi-racial and Hispanic/Latinx, (3) 15.0% Black/African American, (4) 7.1% Hispanic/Latinx, (5) 4.6% multi-racial and non-Hispanic/Latinx, (6) 3.7% Asian, (7) 1.7% American Indian or Alaskan Native, (8) 0.7% Native Hawaiian or Pacific Islander, and (9) 3.0% with no reported race/ethnicity. For comparison, the total sample of adolescents who responded No to the question about concussion was used in some table entries.

Survey questions

The YRBS in 2019 included 99 questions, 89 of which were included in the standard questionnaire and 10 additional questions were added to address other areas of interest. The specific questions, recall periods, response options, and definitions of each variable are included in the YRBS questionnaire and data user's guide available on the website.³⁴ The specific questions used in this study, or variables that were combined based on two or more survey questions, are shown in Table 1.

Table 1.

Survey Questions and Combined Variables Used in This Study

1. Felt Unsafe at School: Q15. During the past 30 days, on how many days did you not go to school because you felt you would be unsafe at school or on your way to or from school? Endorsing 1 or more was coded as “Felt Unsafe at School.”

2. Threatened on School Property: Q16. During the past 12 months, how many times has someone threatened or injured you with a weapon such as a gun, knife, or club on school property? Endorsing 1 or more was coded as “Threatened on School Property.”

3. Sexual Abuse/Assault: QN20. During the past 12 months, how many times did anyone force you to do sexual things that you did not want to do? (Count such things as kissing, touching, or being physically forced to have sexual intercourse. Endorsing this question as 1 or more was coded as “Sexual Abuse/Assault.”

4. Bullied Electronically or at School: Q23. During the past 12 months, have you ever been bullied on school property?

5. Q24. During the past 12 months, have you ever been electronically bullied? (Count being bullied through texting, Instagram, Facebook, or other social media.) Endorsing either Q23 or Q24 as “yes” was coded as “Bullied.”

6. Depression in the Past Year: Q25. During the past 12 months, did you ever feel so sad or hopeless almost every day for two weeks or more in a row that you stopped doing some usual activities? Endorsing this question as “yes” was coded as “Depression in Past Year.”

7. Suicidal Ideation: Q26. During the past 12 months, did you ever seriously consider attempting suicide?

8. Suicide Plan: Q27. During the past 12 months, did you make a plan about how you would attempt suicide?

9. Suicide Attempt: QN28. During the past 12 months, how many times did you actually attempt suicide? This variable was coded as “yes” if the student reported one or more attempts.

10. Currently Smoke Cigarettes: QN32. During the past 30 days, on how many days did you smoke cigarettes? Coded yes if 1 or more.

11. Current Binge Drinking: QN42. During the past 30 days, on how many days did you have 4 or more drinks of alcohol in a row, that is, within a couple of hours (if you are female) or 5 or more drinks of alcohol in a row, that is, within a couple of hours (if you are male)? Coded as “yes” if 1 or more for the variable “Current Binge Drinking.”

12. Used Illicit Drugs 3 or More Times: Reported using one or more of the following drugs 3 or more times during lifetime: (i) prescription pain medication with a prescription; (ii) cocaine; (iii) inhalants; (iv) heroin; (v) methamphetamines; (vi) ecstasy/MDMA; or (vii) used a needle to inject any illegal drug into your body. During your life, how many times have you (i) taken prescription pain medicine without a doctor's prescription or differently than how a doctor told you to use it (Q49); (ii) used any form of cocaine, including powder, crack, or freebase (Q50); (iii) sniffed glue, breathed the contents of aerosol spray cans, or inhaled any paints or sprays to get high (Q51); (iv) used heroin (also called smack, junk, or China White) (Q52); (v) used methamphetamines (also called speed, crystal meth, crank, ice, or meth) (Q53); (vi) used ecstasy (also called MDMA or Molly) (Q54); or (vii) used a needle to inject any illegal drug into your body (Q56)? The QN variables were used for “yes” or “no” and the regular variables were used to classify as 3 or more times.

13. Physically Active 5+ Days: Q78. During the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day? (Add up all the time you spent in any kind of physical activity that increased your heart rate and made you breathe hard some of the time.) Endorsing 5 or more days was coded as “Physically Active 5+ Days.”.

14. Excessive TV/Gaming: Q79. On an average school day, how many hours do you watch TV? Q80. On an average school day, how many hours do you play video or computer games or use a computer for something that is not school work? (Count time spent playing games, watching videos, texting, or using social media on your smartphone, computer, Xbox, PlayStation, iPad, or other tablet.) Responses to items Q79 and Q80 were summed to form Excessive TV/Gaming variable. Those whose sum value exceeded 10 or more were coded as “yes”.

15. Played on One or More Sports Teams: QN82. During the past 12 months, on how many sports teams did you play? (Count any teams run by your school or community groups.) Coded as “yes” if 1 or more teams.

16. Concussion: Q83. During the past 12 months, how many times did you have a concussion from playing a sport or being physically active? Endorsing one or more was coded as “yes.”

17. Insufficient Sleep: Q88. On an average school night, how many hours of sleep do you get? Those who endorsed 5 or fewer hours were coded as “Insufficient Sleep.”

18. Low Grades: Q89. During the past 12 months, how would you describe your grades in school? Those who endorsed “Mostly D's” or “Mostly F's” were classified as “Low Grades.”

19. Opiate Use in Past 30 Days: Q90. During the past 30 days, how many times have you taken prescription pain medicine without a doctor's prescription or differently than how a doctor told you to use it? Endorsing 1 or more was coded as “yes” for “Opiate Use in Past 30 Days.”

Note: These questions were derived from the 2019 YRBS Data User's Guide (https://www.cdc.gov/healthyyouth/data/yrbs/). These questions were selected to represent a diverse range of risk factors identified in previously published studies, many of which are modifiable.

We selected variables that have been associated with suicidality in previously published studies with adolescents—especially those of broad interest to clinicians and educators. We selected diverse variables, some representing past adversity (e.g., sexual abuse) and others representing potentially modifiable risk factors, such as bullying, substance use, and insufficient sleep.

Statistical analyses

Three sets of binary logistic regressions were conducted, with (1) suicidal ideation, (2) making a suicide plan, and (3) attempting suicide as dichotomous dependent variables. The analyses were conducted separately by gender. The variables included in the logistic regressions were selected based on their relevance in previously published studies and for their practical and clinical relevance.

Each suicidality variable was predicted by each of the following variables in bivariate models, with the unadjusted OR reported for each analysis: (1) being physically active for five or more days, (2) being bullied electronically or at school, (3) having on average D or F grades, (4) having insufficient sleep (i.e., five or fewer hours on school nights), (5) current binge drinking, (6) lifetime use of three or more illicit drugs, (7) current marijuana use, and (8) depression.

The specific questions for each of these variables are provided in Table 1. An OR above 1.00 with a 95% confidence interval (CI) not including 1.00 indicated the predictor was associated with greater odds of endorsing the suicidality question, whereas an OR below 1.00 with a 95% CI not including 1.00 indicated the predictor was associated with reduced odds of endorsing the suicidality item. A multi-variable logistic regression was conducted including all predictors in the same model to examine the magnitude of their associations after controlling for the other variables. The ORs can be interpreted in the same manner, but they reflect the increase or decrease in odds of suicidal ideation, suicide planning, and suicide attempt among adolescents with a concussion in the prior year, controlling for all other variables in the model.

We are not attempting to build causal models or examine possible causal associations with these analyses, nor are we attempting to understand the interrelationships among these variables. We are simply illustrating which variables are associated with suicidality when depression is included in the multi-variable model.

A “stress index” was created by summing the binary responses to six of the eight variables included in the logistic regressions. The following six potentially modifiable risk factors were selected to form this stress index: (1) being bullied electronically or at school, (2) having on average D or F grades, (3) having insufficient sleep (i.e., five or fewer hours on school nights), (4) current binge drinking, (5) lifetime use of three or more illicit drugs, and (6) current marijuana use. This index is not an attempt to create a statistical model for predicting suicidality, but rather simply a practical and clinically relevant sum of risk factors.

The frequency distributions and unadjusted univariable analyses of the stress index were examined for boys and girls who endorsed concussion in the past year irrespective of reported depression, and respective subgroups who reported depression, stratified by endorsement of suicidal ideation, suicide plan, and suicide attempts.

Results

In the total sample of adolescents who reported experiencing a concussion and responded to the question assessing suicidal ideation (n = 1683), 25% endorsed experiencing suicidal ideation in the past year. Among adolescents who responded to the question regarding making a suicide plan (n = 1669), 20% endorsed making a plan; and among adolescents who responded to the question regarding making a suicide attempt in the past year (n = 1138), 15% endorsed having attempted suicide in the past year.

Girls endorsed suicidal ideation (31%) more frequently than boys (19%) (χ² [1, 1683] = 31.47, p < 0.001; OR = 1.89 [95% CI: 1.51, 2.37]). Similarly, girls endorsed making a suicide plan (25%) more frequently than boys (17%) (χ² [1, 1669] = 16.99, p < 0.001; OR = 1.65 [95% CI: 1.30, 2.10]). In contrast, girls did not report attempting suicide (17%) more frequently than boys (13%) (χ² [1, 1138] = 2.66, p = 0.10; OR = 1.31 [95% CI: 0.95, 1.82]). The percentages of adolescents endorsing suicidal ideation and attempts, stratified by gender and subgroups, are presented in Table 2.

Table 2.

Percentages of High School Students Endorsing Suicidality

	Total Sample						Girls						Boys
		Suicidal ideation		Suicide plan		Suicide attempt		Suicidal ideation		Suicide plan		Suicide attempt		Suicidal ideation		Suicide plan		Suicide attempt
Group	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%
Total Sample (No Concussion)	9579	18.3%	9546	15.0%	7363	7.9%	5026	23.7%	5006	19.3%	3910	10.6%	4553	12.4%	4540	10.2%	3453	4.7%

Total Sample (Concussion)	1683	24.7%	1669	20.3%	1138	14.9%	753	31.2%	745	24.8%	517	16.8%	930	19.4%	924	16.7%	621	13.4%
Played on One or More Sports Teams	938	24.2%	935	20.3%	798	14.2%	418	29.4%	415	24.6%	355	14.6%	520	20.0%	520	16.9%	443	13.8%
Physically Active 5+ Days	874	21.1%	871	17.0%	655	11.6%	323	27.2%	322	23.9%	240	13.8%	551	17.4%	549	12.9%	415	10.4%
Sexual Abuse/Assault	206	47.1%	206	43.2%	177	35.6%	137	48.2%	137	42.3%	118	29.7%	69	44.9%	69	44.9%	59	47.5%
Bullied Electronically or at School	552	40.9%	546	33.7%	396	25.3%	324	43.8%	320	34.7%	234	24.4%	228	36.8%	226	32.3%	162	26.5%
Felt Unsafe at School	246	41.5%	238	33.2%	148	29.1%	133	45.9%	128	34.4%	79	29.1%	113	36.3%	110	31.8%	69	29.0%
Threatened on School Property	223	41.7%	220	33.2%	154	33.8%	86	54.7%	85	38.8%	57	40.4%	137	33.6%	135	29.6%	97	29.9%
Excessive TV/Gaming	338	27.2%	337	26.4%	225	20.0%	140	32.9%	140	30.7%	94	25.5%	198	23.2%	197	23.4%	131	16.0%
Currently Smoke Cigarettes	149	38.3%	146	33.6%	97	33.0%	51	51.0%	50	48.0%	34	41.2%	98	31.6%	96	26.0%	63	28.6%
Currently Using Marijuana	469	34.1%	463	28.5%	324	21.9%	190	46.8%	187	38.5%	132	29.5%	279	25.4%	276	21.7%	192	16.7%
Current Binge Drinking	315	32.7%	314	29.0%	216	21.8%	148	39.2%	148	34.5%	97	21.6%	167	26.9%	166	24.1%	119	21.8%
Opiate Use in Past 30 Days	163	43.6%	161	38.5%	125	36.8%	85	48.2%	84	38.1%	67	28.4%	78	38.5%	77	39.0%	58	46.6%
Illicit Drugs 3 or More Times	291	44.3%	283	38.2%	180	34.4%	106	55.7%	102	48.0%	64	37.5%	185	37.8%	181	32.6%	116	32.8%
Sleeping 5 or Fewer Hours Nightly	486	32.7%	479	28.0%	317	21.8%	211	40.8%	207	33.3%	141	26.2%	275	26.5%	272	23.9%	176	18.2%
Low Grades (Ds and Fs)	105	36.2%	102	36.3%	60	38.3%	29	44.8%	29	48.3%	15	46.7%	76	32.9%	73	31.5%	45	35.6%
Depression in Past Year	722	46.5%	716	38.0%	515	28.0%	413	49.2%	409	38.9%	290	27.6%	309	43.0%	307	36.8%	225	28.4%

Stress Index: Concussion Sample	1268	24.2%	1260	19.8%	859	13.0%	593	30.5%	588	24.1%	410	14.4%	675	18.7%	672	16.1%	449	11.8%
No Stressors	404	9.7%	403	6.7%	268	6.3%	167	10.2%	166	4.8%	113	4.4%	237	9.3%	237	8.0%	155	7.7%
1 Stressor	402	21.6%	401	17.5%	273	8.4%	198	24.7%	197	21.3%	145	9.7%	204	18.6%	204	13.7%	128	7.0%
2 Stressors	266	37.2%	264	31.4%	189	16.9%	135	50.4%	134	38.8%	92	20.7%	131	23.7%	130	23.8%	97	13.4%
3 Stressors	124	35.5%	123	30.1%	81	21.0%	57	47.4%	56	37.5%	37	27.0%	67	25.4%	67	23.9%	44	15.9%
4 or More Stressors	72	52.8%	69	47.8%	48	47.9%	36	55.6%	35	54.3%	23	47.8%	36	50.0%	34	41.2%	25	48.0%

Stress Index: No Concussion Sample	7823	18.2%	7801	15.0%	5950	7.4%	4138	23.6%	4,126	19.0%	3165	10.3%	3685	12.2%	3675	10.5%	2785	4.1%
No Stressors	3551	7.4%	3547	6.3%	2637	2.3%	1744	9.3%	1,742	7.2%	1297	2.4%	1807	5.6%	1805	5.5%	1340	1.4%
1 Stressor	2515	20.2%	2510	16.3%	1940	7.1%	1356	25.7%	1,353	20.3%	1052	9.2%	1159	13.7%	1157	11.6%	888	4.6%
2 Stressors	1133	31.8%	1124	25.0%	894	13.8%	663	39.5%	657	32.3%	529	18.7%	470	20.9%	467	14.8%	365	6.6%
3 Stressors	441	41.3%	438	35.4%	337	19.6%	266	48.1%	265	40.0%	200	24.0%	175	30.9%	173	28.3%	137	13.1%
4 or More Stressors	183	61.7%	182	55.5%	142	38.0%	109	70.6%	109	60.6%	87	47.1%	74	48.6%	73	47.9%	55	23.6%

Columns labeled n reflect the subgroup sample size and columns labeled % reflect the percent of that subgroup who endorsed suicidal ideation. See Table 1 for definitions of these variables. For comparison, the top row represents the total sample of youth who answered the questions of interest and who reported “no” for experiencing a concussion in the past year. The “Stress Index” is defined by the number of “yes” responses to questions relating to being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, current marijuana use, and depression; participants with missing data on any of the “Stress Index” questions were excluded from those analyses. The “Stress Index: Concussion Sample” includes participants in the sample who provided responses to items included in the “Stress Index.”

Variables associated with suicidal ideation, making a suicide plan, and suicide attempts among girls

Suicidal ideation

The results of the unadjusted univariable and adjusted multi-variable analyses for the girls are presented in Table 3. In unadjusted univariable analyses, endorsement of suicidal ideation was inversely associated with being physically active for five or more days per week, such that those who reported physical activity for five or more days per week were less likely to endorse suicidal ideation. In contrast, suicidal ideation was positively associated with being bullied, insufficient sleep, current binge drinking, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting suicidal ideation in the past year.

Table 3.

Logistic Regressions Predicting Suicidality in Girls

Suicidal ideation
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjusted odds ratio	Lower	Upper	Unadjusted odds ratio	Lower	Upper
Physically Active 5+ Days	-0.42	0.22	3.65	1	.056	0.66	0.43	1.01	0.72	0.53	0.99
Bullied	0.86	0.22	16.21	1	<.001	2.37	1.56	3.61	2.93	2.13	4.04
Low Grades	0.16	0.58	0.08	1	.779	1.18	0.38	3.64	1.86	0.88	3.94
Insufficient Sleep	0.38	0.23	2.82	1	.093	1.46	0.94	2.28	1.84	1.31	2.56
Current Binge Drinking	-0.41	0.27	2.31	1	.129	0.66	0.39	1.13	1.64	1.12	2.39
Illicit Drugs	1.03	0.30	11.99	1	<.001	2.80	1.56	5.03	3.20	2.10	4.89
Currently Using Marijuana	0.90	0.26	12.46	1	<.001	2.47	1.49	4.07	2.64	1.87	3.73
Depression	2.22	0.27	66.99	1	<.001	9.22	5.42	15.70	9.42	6.21	14.29
χ²(8) = 184.305, p < .001, Cox & Snell R² = .269, Nagelkerke R² = .379

Suicide plan
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjustedodds ratio	Lower	Upper	Unadjustedodds ratio	Lower	Upper
Physically Active 5+ Days	-0.01	0.22	0.00	1	.969	0.99	0.64	1.53	0.92	0.66	1.29
Bullied	0.62	0.22	7.91	1	.005	1.87	1.21	2.88	2.48	1.77	3.49
Low Grades	0.55	0.56	0.98	1	.322	1.74	0.58	5.16	3.08	1.46	6.53
Insufficient Sleep	0.39	0.23	2.87	1	.090	1.48	0.94	2.32	1.86	1.30	2.66
Current Binge Drinking	-0.01	0.27	0.00	1	.961	0.99	0.58	1.69	1.92	1.29	2.86
Illicit Drugs	1.36	0.29	22.42	1	<.001	3.91	2.22	6.88	3.49	2.25	5.40
Currently Using Marijuana	0.65	0.26	6.31	1	.012	1.91	1.15	3.16	2.51	1.75	3.61
Depression	1.65	0.27	36.95	1	<.001	5.21	3.06	8.88	7.76	4.93	12.21
χ²(8) = 123.986, p < .001, Cox & Snell R² = .191, Nagelkerke R² = .285

Suicide attempt
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjustedodds ratio	Lower	Upper	Unadjustedodds ratio	Lower	Upper
Physically Active 5+ Days	-0.32	0.32	0.98	1	.323	0.73	0.39	1.36	0.66	0.41	1.06
Bullied	0.82	0.33	6.16	1	.013	2.27	1.19	4.34	2.79	1.71	4.54
Low Grades	0.83	0.82	1.03	1	.310	2.30	0.46	11.45	5.17	1.82	14.73
Insufficient Sleep	0.75	0.32	5.39	1	.020	2.11	1.12	3.98	2.26	1.40	3.65
Current Binge Drinking	-0.39	0.40	0.97	1	.324	0.68	0.31	1.48	1.73	0.98	3.04
Illicit Drugs	0.75	0.41	3.37	1	.067	2.11	0.95	4.69	3.65	2.05	6.51
Currently Using Marijuana	1.29	0.36	13.21	1	<.001	3.64	1.81	7.31	3.24	1.98	5.29
Depression	1.81	0.46	15.21	1	<.001	6.09	2.46	15.10	11.76	5.31	26.05
χ²(8) = 67.453, p < .001, Cox & Snell R² = .152, Nagelkerke R² = .271

See Table 1 for definitions of these variables. These variables were selected because they are known correlates in previously published studies, and they are potentially modifiable. Moreover, they appear associated with suicidality in the present study (Table 2).

In the adjusted multi-variable model, being bullied, illicit drug use, marijuana use, and depression remained significantly associated with suicidal ideation. Endorsement of suicidal ideation was not associated with low grades in either the univariable or multi-variable models.

Making a suicide plan

In unadjusted univariable analyses, endorsement of making a suicide plan was positively associated with being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting making a suicide plan in the past year. In the adjusted multi-variable model, being bullied, illicit drug use, marijuana use, and depression retained their association with making a suicide plan. Endorsement of making a suicide plan was not associated with being physically active for five or more days per week in either the univariable or multi-variable models.

Suicide attempts

In unadjusted univariable analyses, endorsement of suicide attempts was positively associated with being bullied, low grades, insufficient sleep, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting suicide attempts in the past year. In the adjusted multi-variable model, most of those variables retained their association with suicide attempts except for reporting low grades and illicit drug use. Endorsement of suicide attempts was not associated with being physically active for five or more days per week or binge drinking in either the univariable or multi-variable models.

Variables associated with suicidal ideation, making a suicide plan, and suicide attempts among boys

Suicidal ideation

The results of the unadjusted univariable and adjusted multi-variable analyses for the boys are presented in Table 4. In unadjusted univariable analyses, suicidal ideation was positively associated with being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting suicidal ideation in the past year. In the adjusted multi-variable model, only being bullied and depression retained an association with suicidal ideation. Endorsement of suicidal ideation was not associated with being physically active for five or more days per week in either the univariable or multi-variable models.

Table 4.

Logistic Regressions Predicting Suicidality in Boys

Suicidal ideation
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjusted odds ratio	Lower	Upper	Unadjusted odds ratio	Lower	Upper
Physically Active 5+ Days	-0.29	0.24	1.51	1	.220	0.75	0.47	1.19	0.73	0.53	1.01
Bullied	0.83	0.25	11.33	1	<.001	2.29	1.41	3.72	3.81	2.69	5.39
Low Grades	0.03	0.40	0.01	1	.944	1.03	0.47	2.27	2.15	1.29	3.59
Insufficient Sleep	0.03	0.25	0.01	1	.917	1.03	0.63	1.66	1.85	1.32	2.60
Current Binge Drinking	0.21	0.30	0.47	1	.494	1.23	0.68	2.23	1.86	1.25	2.78
Illicit Drugs	0.55	0.29	3.56	1	.059	1.74	0.98	3.10	3.34	2.32	4.80
Currently Using Marijuana	0.21	0.27	0.60	1	.437	1.23	0.73	2.10	1.85	1.31	2.62
Depression	2.25	0.24	86.11	1	<.001	9.50	5.90	15.28	10.02	6.83	14.69
χ²(8) = 152.694, p < .001, Cox & Snell R² = .204, Nagelkerke R² = .329

Suicide plan
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjustedodds ratio	Lower	Upper	Unadjustedodds ratio	Lower	Upper
Physically Active 5+ Days	-0.66	0.24	7.37	1	.007	0.52	0.32	0.83	0.53	0.37	0.75
Bullied	0.62	0.26	5.66	1	.017	1.86	1.12	3.09	3.65	2.54	5.25
Low Grades	-0.07	0.43	0.02	1	.878	0.94	0.41	2.16	2.50	1.47	4.24
Insufficient Sleep	0.21	0.25	0.71	1	.401	1.24	0.76	2.02	2.00	1.39	2.86
Current Binge Drinking	0.14	0.32	0.20	1	.652	1.15	0.62	2.15	1.86	1.22	2.82
Illicit Drugs	0.61	0.30	4.18	1	.041	1.84	1.03	3.32	3.06	2.09	4.48
Currently Using Marijuana	0.26	0.28	0.82	1	.365	1.29	0.74	2.24	1.79	1.24	2.59
Depression	1.98	0.25	61.04	1	<.001	7.27	4.42	11.96	8.54	5.73	12.73
χ²(8) = 118.912, p < .001, Cox & Snell R² = .163, Nagelkerke R² = .280

Suicide attempt
							95% Confidence interval			95% Confidence interval
	B	SE	Wald	df	p	Adjustedodds ratio	Lower	Upper	Unadjustedodds ratio	Lower	Upper
Physically Active 5+ Days	-0.72	0.34	4.51	1	.034	0.49	0.25	0.95	0.49	0.31	0.78
Bullied	0.78	0.34	5.30	1	.021	2.19	1.12	4.26	3.86	2.39	6.24
Low Grades	0.60	0.54	1.23	1	.268	1.82	0.63	5.26	4.36	2.24	8.49
Insufficient Sleep	-0.07	0.35	0.04	1	.852	0.94	0.47	1.86	1.72	1.06	2.79
Current Binge Drinking	0.62	0.43	2.08	1	.150	1.86	0.80	4.32	2.52	1.46	4.32
Illicit Drugs	0.64	0.40	2.59	1	.108	1.90	0.87	4.14	4.56	2.77	7.50
Currently Using Marijuana	-0.03	0.40	0.01	1	.939	0.97	0.45	2.11	1.69	1.03	2.77
Depression	2.28	0.40	32.19	1	<.001	9.77	4.45	21.48	8.28	4.76	14.42
χ²(8) = 77.938, p < .001, Cox & Snell R² = .160, Nagelkerke R² = .309

Making a suicide plan

In unadjusted univariable analyses, endorsement of making a suicide plan was inversely associated with being physically active for five or more days per week, such that those who reported physical activity for five or more days per week were less likely to endorse making a suicide plan. In contrast, endorsement of making a suicide plan was positively associated with being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting making a suicide plan in the past year. In the adjusted multi-variable model, being bullied and illicit drug use retained their association with making a suicide plan.

Suicide attempts

In unadjusted univariable analyses, endorsement of suicide attempts was inversely associated with being physically active for five or more days per week, such that those who reported physical activity for five or more days per week were less likely to endorse suicide attempts. In contrast, reporting of suicide attempts was positively associated with being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, marijuana use, and depression, such that endorsement of these variables was associated with increased likelihood of reporting suicide attempts in the past year. In the adjusted multi-variable model, only being physically active for five or more days per week, being bullied, and depression retained their associations with suicide attempts.

Stress index in girls and boys

Frequencies of cumulative stress factors in girls and boys are displayed in Table 5. Among girls, univariable unadjusted analyses revealed a positive association between cumulative risk factors and suicidal ideation, making a suicide plan, and suicide attempts. The presence of additional stress factors was associated with greater proportions of those who endorsed suicidal ideation (i.e., 25–56%), making a suicide plan (i.e., 21–53%), and suicide attempts (i.e., 7–31%). The absence of risk factors was associated with much lower proportions endorsing suicidal ideation (i.e., 10%), making a suicide plan (i.e., 5%), and suicide attempts (i.e., 5%).

Table 5.

Cumulative Risk Factor Model Predicting Suicidality in Adolescents

	Suicidal ideation
	Girls					Boys
				95% Confidence interval					95% Confidence interval
	n	%	Unadjusted odds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	167	10.2%	0.18	0.11	0.31	237	9.3%	0.33	0.20	0.54
1 Stressor	198	24.7%	2.90	1.60	5.27	204	18.6%	2.24	1.27	3.93
2 Stressors	135	50.4%	8.96	4.89	16.39	131	23.7%	3.03	1.67	5.50
3 Stressors	57	47.4%	7.94	3.86	16.35	67	25.4%	3.32	1.64	6.72
4 or More Stressors	36	55.6%	11.03	4.82	25.22	36	50.0%	9.77	4.45	21.47

	Suicide plan
	Girls					Boys
				95% Confidence interval					95% Confidenceinterval
	n	%	Unadjustedodds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	166	4.8%	0.11	0.05	0.23	237	8.0%	0.34	0.20	0.57
1 Stressor	197	21.2%	5.35	2.43	11.77	204	13.7%	1.83	0.99	3.38
2 Stressors	134	38.5%	12.52	5.68	27.62	130	23.7%	3.59	1.94	6.67
3 Stressors	56	36.8%	11.85	4.85	28.94	67	23.9%	3.60	1.73	7.48
4 or More Stressors	35	52.8%	23.45	8.86	62.06	34	38.9%	8.03	3.51	18.39

	Suicide attempt
	Girls					Boys
				95% Confidence interval					95% Confidenceinterval
	n	%	Unadjustedodds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	113	5.1%	0.21	0.08	0.54	155	5.1%	0.52	0.26	1.02
1 Stressor	145	7.1%	2.31	0.81	6.61	128	4.4%	0.90	0.37	2.21
2 Stressors	92	14.1%	5.62	2.01	15.73	97	9.9%	1.84	0.81	4.23
3 Stressors	37	17.5%	8.00	2.53	25.35	44	10.4%	2.26	0.83	6.13
4 or More Stressors	23	30.6%	19.80	5.88	66.65	25	33.3%	11.00	4.12	29.34

The column labeled n reflects the subgroup sample size and columns labeled % reflect the percent of that subgroup who endorsed suicidal ideation or suicide attempts. The “Stress Index” is comprised of the following variables: being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, and current marijuana use. These analyses include adolescents who did and did not endorse depression.

Notably, ORs for suicidality appeared to show the largest change in magnitude when increasing from three to four stress factors. For example, 17.5% of girls with three stressors reported a suicide attempt, whereas 31% of girls with four or more stressors reported a suicide attempt.

Frequencies of cumulative stress factors in boys are displayed in Table 5. Univariable unadjusted analyses revealed a positive association between cumulative risk factors, at higher levels, and suicidal ideation, making a suicide plan, and suicide attempts. The presence of additional stress factors was associated with greater proportions of those who endorsed suicidal ideation (i.e., 19–50%), making a suicide plan (i.e., 14–39%), and suicide attempts (i.e., 5–33%). The absence of risk factors was associated with much lower proportions endorsing suicidal ideation (i.e., 9%) and making a suicide plan (i.e., 8%), and suicide attempts (i.e., 5%).

Similar to girls, ORs for suicidality showed the largest change in magnitude when increasing from three to four stress factors. For example, 10% of boys with three stressors reported a suicide attempt, whereas 33% of boys with four or more stressors reported a suicide attempt.

Stress index in girls and boys endorsing depression

Frequencies of stress factors in the subsample of girls and boys endorsing depression in the past year are displayed in Table 6. Among girls, univariable unadjusted analyses revealed a positive association between stress factors and suicidal ideation, making a suicide plan, and suicide attempts. The presence of additional stress factors was associated with a greater proportion endorsing suicidal ideation (i.e., 42–72%), making a suicide plan (i.e., 30–75%), and suicide attempts (i.e., 16–62.5%). Among boys, univariable unadjusted analyses revealed a positive association between four or more stress factors and suicidal ideation, making a suicide plan, and suicide attempts. The presence of additional stress factors was associated with a greater proportion endorsing suicidal ideation (i.e., 38–71%), making a suicide plan (22.5–65%), and suicide attempts (11–60%).

Table 6.

Cumulative Risk Factor Model Predicting Suicidality in Adolescents Endorsing Depression

	Suicidal ideation
	Girls					Boys
				95% Confidence interval					95% Confidence interval
	n	%	Unadjusted odds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	47	29.8%	0.38	0.19	0.73	48	27.1%	0.40	0.20	0.80
1 Stressor	101	41.6%	1.68	0.80	3.52	71	38.0%	1.65	0.75	3.67
2 Stressors	107	58.9%	3.38	1.62	7.03	50	52.0%	2.92	1.25	6.79
3 Stressors	44	54.5%	2.83	1.20	6.70	32	50.0%	2.69	1.05	6.90
4 or More Stressors	25	72.0%	6.06	2.07	17.74	21	71.4%	6.73	2.15	21.06

	Suicide plan
	Girls					Boys
				95% Confidence interval					95% Confidenceinterval
	n	%	Unadjustedodds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	47	12.8%	0.20	0.08	0.49	48	22.9%	0.45	0.21	0.94
1 Stressor	100	30.0%	2.93	1.12	7.63	71	22.5%	0.98	0.41	2.34
2 Stressors	106	44.3%	5.44	2.13	13.91	50	52.0%	3.64	1.52	8.72
3 Stressors	44	45.5%	5.69	2.01	16.15	32	43.8%	2.62	0.99	6.90
4 or More Stressors	24	75.0%	20.50	5.82	72.27	20	65.0%	6.25	2.00	19.51

	Suicide attempt
	Girls					Boys
				95% Confidence interval					95% Confidenceinterval
	n	%	Unadjustedodds ratio	Lower	Upper	n	%	Unadjusted odds ratio	Lower	Upper
No Stressors	31	9.7%	0.32	0.09	1.08	36	20.8%	1.04	0.45	2.38
1 Stressor	76	15.8%	1.75	0.46	6.70	53	11.3%	0.33	0.11	1.02
2 Stressors	76	25.0%	3.11	0.85	11.40	35	37.1%	1.54	0.57	4.18
3 Stressors	29	31.0%	4.20	1.01	17.50	23	26.1%	0.92	0.28	2.99
4 or More Stressors	16	62.5%	15.56	3.26	74.23	15	60.0%	3.90	1.10	13.81

The column labeled n reflects the subgroup sample size and columns labeled % reflect the percent of that subgroup who endorsed suicidal ideation or suicide attempts. The “Stress Index” comprises the following variables: being bullied, low grades, insufficient sleep, current binge drinking, illicit drug use, and current marijuana use.

Discussion

Researchers using CDC survey data from high school students in the United States have reported an association between sustaining a concussion and suicidality.^4-–8 In a recent study, however, examining multi-variable models that control for a broad range of other risk factors for suicidality, the associations between concussion and suicidality were greatly attenuated or became nonsignificant.⁹

For the present study, we adopted a different methodology than all previous studies on this topic by focusing specifically on youth who reported sustaining a concussion during the past year as the sample of interest. This allows us to draw inferences regarding youth who have been concussed, and factors associated with suicidality for them—as opposed to studying concussion, per se, as a factor of interest in relation to suicidality. This methodology is more clinically relevant because we are examining correlates of suicidality in youth who have been injured.

One of three (31%) girls and one of five (19%) boys who reported sustaining a concussion in the past year also reported experiencing suicidal ideation in the past year. Moreover, many of these adolescents reported attempting suicide in the past year (17% of girls and 13% of boys). There were numerous important correlates, or risk factors, for suicidality in both girls and boys, such as being bullied, being threatened or feeling unsafe at school, using illicit drugs (and opiates), and getting very low grades in school (Table 2). By far, the strongest predictor of all forms of suicidality, in both girls and boys, was experiencing depression (Tables 3-4).

In multi-variable analyses, however, that include depression, other modifiable risk factors remained significant. For girls, illicit drug use, marijuana use, and being bullied were independent risk factors (Table 3). Insufficient sleep was also an independent risk factor for planning suicide for girls. For boys, after controlling for depression, only being bullied was a consistent risk factor for suicidality. Being physically active for five or more days per week was independently associated with a lower likelihood of endorsing making a suicide plan and suicide attempts in boys (Table 4).

It is remarkably difficult to predict suicidality in youth, both at the population level and, of course, for individuals—and in the present study the amount of variance in suicidality accounted for by the predictors was modest. The amount of variance accounted for by the eight predictors, for girls, was lower for suicide attempts than for suicide ideation.

For the present study, we created a stress index comprised of potentially modifiable risk factors to examine the association between cumulative stressors and suicidality in youth who have sustained concussions. Previously published studies have illustrated that the six variables within the stress index—(1) being bullied,^13,15

–18 (2) having on average D or F grades,⁹ (3) having insufficient sleep (i.e., five or fewer hours on school nights),³⁰ (4) binge drinking, (5) illicit drug use,^13,23 and (6) marijuana use^19,22,23—are all associated with suicidality in high school students.

These variables are of practical, clinical, and societal interest. In the present study, for those students who denied all six stressors, approximately one of 10 endorsed suicidal ideation (9% of boys and 10% of girls). In contrast, for those who endorsed experiencing three of the stressors, one in four boys (25%) and half of the girls (47%) endorsed suicidal ideation.

In this study, we made no attempt to examine possible causal associations or to estimate how exposure (predictor) variables were interrelated. Future researchers could attempt to use YRBS data to examine specific combinations of risk factors and predictor variables, guided by clinical considerations, using a priori theorizing about possible causal and mediational relationships. Directed acyclic graphs could be used, methodologically, to examine theories and assumptions about the relationships among these variables.³⁵

Limitations

This study has several important limitations. First, we cannot draw inferences regarding causation. Specifically, it is not known whether concussion is directly or indirectly causally related to suicidality in high school students because this was a cross-sectional survey study for which we do not know when the students experienced their concussion or when they experienced suicidality. Second, we have no information in the survey about the mechanisms of injury, severity of injury, co-occurring injuries, clinical outcomes, or recovery times from the students' concussions.

Third, our stress index is not a validated index. It is an outcome measure of convenience created for this study, and we included variables, based on clinical experience and a review of the literature, that seemed clinically relevant and, importantly, modifiable through intervention. Fourth, all information was self-reported by the students; we do not know how accurate it is, and we do not know whether some students' approach to the survey was influenced by a response bias such as nay-saying (a response set of answering questions negatively regardless of the content) and yea-saying (an acquiescent response set). Notably, the percentage of adolescents reporting a concussion in the past year aligns with large-scale study of high school athletes.³⁶ Fifth, cell sizes were smaller than desirable for logistic regressions examining subsets of the sample (e.g., boys with four or more stressors).

Conclusions

This study has important clinical implications. First, a substantial number of high school students who sustain a concussion report experiencing suicidality, with rates modestly higher than in youth who have not sustained a concussion. Second, there is a very strong association, as expected, between experiencing depression and suicidality. Third, psychosocial stressors, such as bullying, are independently related to suicidality after controlling for depression. Finally, the experience of cumulative modifiable stressors is strongly associated with suicidality—meaning that adolescents who report no major stressors have a relatively low rate of suicidality but adolescents who report three or more life stressors have a high rate of suicidality.

Therefore, clinicians and school personnel should be watchful for not only depression in adolescents who have experienced concussions, but also cumulative life stressors. These at-risk youth should be referred for mental health services.

Transparency, Rigor, and Reproducibility Summary

This was not a pre-registered study. This study relied on secondary analyses of a publicly available national survey of high school students in the United States. The Youth Risk Behavior Surveillance System (YRBSS) 2019 national dataset is available online: Centers for Disease Control and Prevention. [2019] Youth Risk Behavior Survey Data.³⁴ There is extensive documentation on the website relating to their survey methodology and also a summary article for the 2019 survey³ See the opening paragraph, of the “Sample” section of the current manuscript for a synopsis of information on transparency and rigor regarding the survey methodology.

Data analyses were conducted using SPSS (version 28.0). Analyses included reporting on item endorsement frequencies stratified by gender. Univariable and multi-variable logistic regressions were conducted to obtain odds ratios to characterize associations between reported behaviors and suicidality. Because of data limitations, some of the exploratory logistic regression models were not sufficiently powered to detect statistically significant associations. Coding syntax are available on reasonable request. We plan to conduct replication studies on publication of updated YRBS data.

Footnotes

Acknowledgments

The data used in the current study were from the Youth Risk Behavior Surveillance System (YRBSS) 2019 national dataset, which is publicly available online: Centers for Disease Control and Prevention. [2019] Youth Risk Behavior Survey Data.³⁴

Authors' Contributions

Grant L. Iverson, PhD, conceptualized the study, conducted the literature review, helped conceptualize the statistical analyses, and drafted portions of the manuscript. Charles E. Gaudet, PhD, conducted the statistical analyses, created the tables, drafted the section, and edited drafts of the manuscript. Justin E. Karr, PhD, assisted with conceptualizing the study and statistical analyses, supervised the analyses, and edited drafts of the manuscript. All authors reviewed and approved the final manuscript.

Funding Information

This was not a sponsored study, and no direct funding for this study was provided. Grant Iverson, PhD, has received unrestricted philanthropic support from ImPACT Applications, Inc., the Mooney-Reed Charitable Foundation, the National Rugby League, the Boston Bolts, and the Spaulding Research Institute. None of the above entities were involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication.

Author Disclosure Statement

Grant L. Iverson, PhD, serves as a scientific advisor for NanoDx^® Inc., Sway Operations, LLC, and Highmark, Inc. He has a clinical and consulting practice in forensic neuropsychology, including expert testimony, involving individuals who have sustained mild TBIs (including athletes). He has received research funding from several test publishing companies, including ImPACT Applications, Inc., CNS Vital Signs, and Psychological Assessment Resources (PAR, Inc.). He has received research funding as a principal investigator from the National Football League, and salary support as a collaborator from the Harvard Integrated Program to Protect and Improve the Health of National Football League Players Association Members. Charles E. Gaudet, PhD, and Justin E. Karr, PhD, declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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