Changes in State and Trait Anxiety Throughout Concussion Recovery in High School– and College–Aged Individuals

Study Design and Participants

We used a prospective cohort study with a case-control, repeated-measures design to characterize anxiety throughout recovery. A total of 78 participants were enrolled; 39 high school– and college–aged patients with concussion (25 males and 14 females; age = 18.4 ± 2.3 years) in the mid-Michigan area were matched to 39 uninjured control individuals (25 males and 14 females; age = 18.4 ± 2.3 years) on sex, age, and, when possible, contact sport (n = 62). Inclusion criteria were no history of a neurologic disease (eg, epilepsy), age between 14 and 24 years, and written informed assent and consent, as appropriate, from the participant and a parent or guardian. Exclusion criteria were no testing within 72 hours of injury, a visible abnormality on computed tomography scan, loss of consciousness for ≥20 minutes, or hospital admission for >24 hours due to the head injury or collateral injuries. Recruits were excluded from the uninjured matched control group if they had a concussion within the past year. This study received approval from the University of Michigan Institutional Review Board.

Operational Definitions

Instrumentation

Procedures

Patients with a concussion were recruited via an established network of athletic trainers and health clinics at nearby universities, colleges, and high schools. Clinicians in these networks contacted the study team when a patient received a concussion diagnosis, and trained research coordinators (A.J.Z. and C.P.T.) travelled to the school to enroll the patient and administer the study procedures. Uninjured matched control participants were recruited through patients with concussion and recruitment flyers.

Participants with a diagnosed concussion were tested within 72 hours of injury (day 0: first test session), 5 days (±1 day) from the first test session (day 5), and at the time of FMC (+2 days). Uninjured matched control individuals were tested following the same schedule as their matched participant with concussion. On day 0, we collected demographic and medical history and concussion characteristics (for the concussion group only) and administered the STAI. For the subsequent visits (day 5), FMC participants completed the STAI. All data were collected using pen and paper and were transcribed into an Excel (version 2016; Microsoft Corp) spreadsheet by a study coordinator (C.P.T.).

Statistical Analysis

Descriptive statistics were calculated for the demographic and medical history variables in the concussion and control groups. Independent-samples t tests were used to compare continuous demographic characteristics, and the χ² test was used to compare categorical variables between groups. Separate 2 × 3 repeated-measures analyses of variance were computed to investigate changes in state and trait anxiety for each group throughout recovery. Within-subject variables were time (day 0, day 5, and FMC), and between-subjects variables were group (concussion and uninjured matched control). Estimates of the effect size for each repeated-measures analysis of variance were determined as partial η² (ƞ_p²). Greenhouse-Geisser ε corrections were applied when the assumption of sphericity was violated. Interactions were further explored via independent-samples t tests as post hoc testing at each time point. For the post hoc t tests, we estimated Cohen d effect sizes, which we interpreted as small (d = 0.2), medium (d = 0.5), or large (d = 0.8).²³ We set the α level a priori at .05. All statistical analyses were completed using SPSS (version 27; IBM Corp).

Demographic Characteristics and Medical History

No differences in demographic characteristics and medical history were found between groups (Table 1). Of note, 5 (12.8%) participants in the concussion group and 2 (5.1%) participants in the uninjured matched control group reported a history of depression or anxiety (P = .23). The average time from concussion to day 0 was 2.2 ± 0.8 days, to day 5 was 5.5 ± 1.0 days, and to FMC was 11.6 ± 14.4 days. On average, participants in the control group were enrolled within 7.02 ± 39 days of the participants in the concussion group to whom they were matched. Furthermore, we observed no differences in the timing of visits and, subsequently, the timing of STAI assessments between groups (Table 2).

Table 1 Participant Characteristics

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Table 2 Time Between Visits and State-Trait Anxiety Inventory Assessments in the Concussion and Matched Control Groups

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State Anxiety

We observed a group × time interaction (F_2,150 = 10.45, P < .001, ƞ_p² = 0.12), indicating that the change in state anxiety scores over time differed by group membership. The post hoc analysis revealed that the concussion group reported a higher level of state anxiety than the control group at each time (Table 3). In both groups, state anxiety was highest on day 0 and decreased across time. On day 0, 56.4% (n = 22) of the concussion and 10.3% (n = 4) of the uninjured matched control group had scores above the clinical cutoff of 38 for a high level of state anxiety. On day 5, 38.5% (n = 15) of the concussion and 12.8% (n = 5) of the control group had scores >38. At FMC, 20.5% (n = 8) of the concussion and 7.7% (n = 3) of the uninjured matched control group had scores >38.

Table 3 State Anxiety Scores on the State-Trait Anxiety Inventory in the Concussion and Matched Control Groups Over Time

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Trait Anxiety

No group × time interaction was found (F_1.74,150 = 1.5, P = .22, ƞ_p² = 0.02), although main effects for time (F_1.74,150 = 25.7, P < .001, ƞ_p² = 0.3) and group (F_1,75 = 7.23, P = .01, ƞ_p² = 0.09) were seen. At each time, the concussion group reported more trait anxiety than the control group (Table 4). In both groups, trait anxiety was highest on day 0 and decreased across time. On day 0, 15.4% (n = 6) of the concussion and 2.6% (n = 1) of the control group had scores above the clinical cutoff of 52 for a high level of trait anxiety. On day 5, 12.8% (n = 5) of the concussion and 2.6% (n = 1) of the control group had scores >52. At FMC, 10.3% (n = 4) of the concussion and 2.6% (n = 1) of the control group had scores >52.

Table 4 Trait Anxiety Scores on the State-Trait Anxiety Inventory in the Concussion and Matched Control Groups Over Time, Mean ± SD

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State Anxiety Throughout Recovery

Previous researchers^14,19 have suggested that anxiety symptoms increase after concussion and that measuring state anxiety affords clinicians the opportunity to efficiently assess these emotional responses. The STAI classifies a high level of state anxiety as a score >38, which can indicate a current anxiety response.²² On day 0, 56.4% of the concussion group had scores above the clinical cutoff for a high level of state anxiety; however, by FMC, only 20.5% of the concussion group had scores above this clinical cutoff. The results suggest that individuals with concussion were at the greatest risk for increased anxiety symptoms during the days immediately after injury but still had a greater emotional response at all 3 times than their uninjured counterparts.

Heightened state anxiety during the acute phase of injury may be attributed to the uncertainty and confusion participants had surrounding the concussive incident and the potential for further harm.^21,24,25 This possibility is further supported by a systematic review of student-athletes in which the investigators²⁴ identified the most common barriers to reporting concussion symptoms as fears of losing current or future playing time and letting their team down. In addition, Anderson et al²⁵ reported that athletes with more fear of reinjury after a concussion had more affective symptoms than those with less fear of reinjury. These fears could induce feelings of apprehension and tension when individuals are removed from normal activities and begin concussion treatment. However, we did not examine the fear of reinjury, and it should be considered for future research.

The concussion group had higher levels of state anxiety throughout recovery than the control group. These results are similar to those of Turner et al,¹⁹ who also reported elevated levels of state anxiety at both the start of the stepwise concussion protocol and return to play in collegiate athletes. The persistence of state anxiety throughout recovery may represent the patients’ anxiety about how the concussion might affect everyday life, such as not knowing what to expect during recovery or concern that their symptoms would not improve.²¹ Even though the level of state anxiety at FMC for the concussion group did not exceed the cutoff score, it could still indicate these individuals were anxious when they were expected to resume normal activities.¹⁹ Earlier authors²⁶ suggested that these individuals may be at risk for subsequent injury or other consequential health outcomes. Finally, we observed a decline in state anxiety for the control group that could be attributed to external factors not captured in this study (eg, attenuation effect, life events, academic responsibilities).²⁷

Trait Anxiety Throughout Recovery

Unlike state anxiety, which represents the current emotional state of individuals, trait anxiety represents the part of personality that influences the initiation of anxiety responses.²² Therefore, it is considered a stable predisposition and may not be susceptible to dramatic change after injury. Our result of no interaction supported this notion, as did previous research²⁸ that demonstrated no differences in trait anxiety across concussion recovery. Nonetheless, main effects were present between groups and over time, suggesting that the concussion group may simply have had a higher predisposition to experiencing anxiety responses than their counterparts.

Furthermore, high levels of trait anxiety can be a potential indicator of future injury.²⁹ Concerning concussion, in a systematic review, Trinh et al³⁰ described a relationship between preexisting psychological factors (eg, life stressors, emotional states, Big Five personality traits) and the incidence and severity of sport-related concussion. Thus, the greater trait anxiety in the concussion group may have indicated that they were already more susceptible to injury and resulted in the higher state anxiety levels throughout recovery. Unfortunately, this cannot be explicitly determined because baseline trait anxiety levels were not collected, but future researchers should focus on the mediating interaction between trait anxiety level and concussion incidence. Overall, these findings add to the current understanding of postconcussion anxiety and its role in recovery.

Clinical Implications

The anxiety and mood clinical profile is the second most common single profile, representing 25% of patients with concussion.⁴ We noted an increase in state anxiety during the acute phase of concussion for the concussion group compared with that in the control group. The STAI could be used as a clinical tool pre- and postconcussion to identify individuals who may be at risk (eg, history of psychiatric conditions, significant life stressors) or experiencing state anxiety responses throughout recovery due to their concussion. Although a baseline STAI was not administered in this study, understanding individuals’ baseline emotional states is important for evaluating possible postconcussion changes in state anxiety or those with higher trait anxiety who may be at risk for prolonged recovery. Using the STAI could help identify individuals who may require a referral to appropriate licensed professionals (eg, sports psychologist, clinical psychologist) pre- or postconcussion. In addition, incorporating the STAI into assessment and management after a concussion could allow clinicians to provide specific targeted treatments for individuals with high state anxiety. Targeted treatments such as active rehabilitation programs,³¹ psychotherapy,³² and cognitive behavioral therapy³³ reduced anxiety symptoms postconcussion in pediatric and adult populations.

Limitations

This study had limitations. First, our sample consisted of high school– and college–aged individuals in the mid-Michigan area, yet their mean age was 18 years. Moreover, our participants were those who reported their concussion to a health care provider. We did not account for unreported concussions or individuals who declined to participate in the study. However, trained researchers worked with individuals at multiple visits, which can lead to greater comfort in the laboratory with the researchers and, thus, more likelihood of participating. Therefore, future investigations should include youth and older adults to permit generalizability. Second, as with all self-report surveys, participants may not have been honest in their answers on the STAI. Third, we did not conduct a baseline assessment of trait anxiety. A baseline assessment could confirm that no interaction existed between baseline and postconcussion anxiety, which could then show that trait anxiety remains stable over time. Fourth, participants with concussion could have typically experienced more anxiety (ie, trait) that translated into greater vulnerability to anxiety postinjury (ie, state). Similarly, we included individuals with a history of depression or anxiety, which might have contributed to anxiety postinjury (ie, state). Yet we observed no differences between groups for their history of anxiety or depression, so we did not remove these participants from the study. Finally, our sample size was small; future authors should replicate our work and demonstrate generalizability to other samples. Future researchers should also examine the effect of high trait anxiety on concussion incidence, determine if high levels of postconcussion state anxiety yield longer recovery times, and assess the influence of specific treatments on reducing state anxiety postinjury.