Despite consensus that personality influences mild traumatic brain injury (mTBI) recovery, it has been underexamined. We evaluated the extent to which diverse personality and psychiatric symptom dimensions predict mTBI recovery.

This prospective cohort study involved psychological assessments of hospital patients with mTBI (n = 75; median = 2 days post-injury, range = 0–12 days) and orthopedic trauma controls (OTC; n = 79) who were used for comparison in mediation modeling. Chronic symptoms were evaluated at 3 months after mTBI (n = 50) using the Sport Concussion Assessment Tool (SCAT) symptom checklist. Linear regression analyses were used to identify the predominant predictors of chronic symptoms in mTBI. Modern mediation analyses tested the hypothesis that personality traits predict chronic symptoms through acute psychological response to injury.

In mTBI, trait psychoticism directly predicted chronic mTBI symptoms and was the strongest personality predictor overall. Furthermore, an internalizing personality dimension emphasizing negative affect/emotionality and detachment predicted chronic mTBI symptoms indirectly through enhancement of acute somatic complaints. In OTC, internalizing personality acted through the same mediator as in mTBI, whereas the effect of psychoticism was also mediated through acute somatic complaints. There was varying support for a moderated direct effect of personality traits at low levels of positive emotionality across models.

These causal models provide novel insights about the role of personality in mTBI symptom recovery, highlighting the complexity of how psychological processes may interact to affect recovery and revealing that some of these processes may be non-specific to brain injury.