Several factors have been linked to severity of postconcussive-type (neurobehavioral) symptoms. In this study, predictors of neurobehavioral symptoms were examined using multivariate methods to determine the relative importance of each. Data regarding demographics, symptoms, current alcohol use, history of traumatic brain injury (TBI), orthopedic injuries, and psychiatric/developmental diagnoses were collected via questionnaire from 3027 university students. The most prominent predictors of symptoms were gender, history of depression or anxiety, history of attention-deficit/hyperactivity disorder or learning disability diagnosis, and frequency of alcohol use. Prior mild TBI was significantly related to overall symptoms, but this effect was small in comparison to other predictors. These results provide further evidence that neurobehavioral symptoms are multi-determined phenomena, and highlight the importance of psychiatric comorbidity, demographic factors, and health behaviors to neurobehavioral symptom presentation after mild TBI. (JINS, 2013, 19, 1–9)

Impulsive behaviors and poor inhibition performances are frequently described in patients with traumatic brain injury (TBI). However, few studies have examined impulsivity and associated inhibition impairments in these patients. Twenty-eight patients with moderate to severe TBI and 27 matched controls performed a stop-signal task designed to assess prepotent response inhibition (the ability to inhibit a dominant or automatic motor response) in a neutral or emotional context and a recent negative task to assess resistance to proactive interference (the ability to resist the intrusion into memory of information that was previously relevant but has since become irrelevant). Informants of each patient completed a short questionnaire designed to assess impulsivity. Patients showed a significant increase in current urgency, lack of premeditation, and lack of perseverance when retrospectively compared with the preinjury condition. Group comparisons revealed poorer prepotent response inhibition and resistance to proactive interference performances in patients with TBI. Finally, correlation analyses revealed a significant positive correlation between urgency (the tendency to act rashly when distressed) and prepotent response inhibition in patients with TBI. This study sheds new light on the construct of impulsivity after a TBI, its related cognitive mechanisms, and its potential role in problematic behaviors described after a TBI. (JINS, 2013, 19, 1–9)