Table 1 Demographic, preinjury and injury characteristics of the participants
VariablemTBI (n = 90)Controls (n = 85)p Value
Age at injury (y) (mean (SD))34.7 (13.7)34.6 (12.1)0.780*
Years of education (mean (SD))11.5 (2.8)11.5 (2.5)0.590
Full Scale IQ (mean (SD))99.8 (10.4)99.8 (9.8)0.912
Assessed (days) (mean (SD))4.8 (2.8)5.0 (2.5)0.310
AUDIT6.6 (6.5)5.2 (6.3)0.015
Injury severity score (mean (SD))5.4 (6.2)5.5 (5.3)0.329
Pain3.6 (2.4)3.9 (2.6)0.635
mTBI (n = 51)Controls (n = 55)
Opioids, MDE (mean (SD))49.5 (87.6)39.5 (38.1)0.831
Sex (n (%))
    Males61 (67.8)55 (64.7)
    Females29 (32.2)30 (35.3)0.667†
No of prior mTBI (n (%))
    None53 (58.9)64 (75.3)
    One30 (33.3)11 (12.9)
    More than one7 (7.8)10 (11.8)0.006
Marijuana use
    No67 (74.4)68 (80.0)
    Yes23 (25.6)17 (20.0)0.382
Medical history (n (%))
    No72 (80.0)66 (77.6)
    Yes18 (20.0)19 (22.4)0.703
Cause of injury (n (%))
    Motor vehicle accident73 (81.1)63 (74.1)
    Fall/jump10 (11.1)16 (18.8)
    Assault5 (5.6)4 (4.7)
    Other2 (2.2)2 (2.4)0.542‡
Glasgow Coma Scale (n (%))
    132 (2.2)
    1411 (12.1)
    1577 (85.7)
Duration of PTA (n (%))
    <5 min33 (36.7)
    6–60 min20 (22.2)
    61 min to 12 h21 (23.3)
    >12 h to 24 h16 (17.8)
  • Assessed (days), number of days assessed since trauma.

  • Medical history includes individuals with a history of epilepsy, diabetes, hypertension and cardiac disease.

  • Pain was measured on a numerical rating scale at the time of assessment.

  • AUDIT, Alcohol Use Disorders Identification Test; MDE, morphine dose equivalents; mTBI, mild traumatic brain injury, PTA, post-traumatic amnesia.

  • *Mann–Whitney U tests.

  • †χ2 analyses.

  • ‡Fisher’s exact test.