Objective To assess the association between mind wandering (thinking unrelated to the task at hand) and the risk of being responsible for a motor vehicle crash.Design Responsibility case-control study.Setting Adult emergency department of a university hospital in France, April 2010 to August 2011.Participants 955 drivers injured in a motor vehicle crash.Main outcome measures Responsibility for the crash, mind wandering, external distraction, negative affect, alcohol use, psychotropic drug use, and sleep deprivation. Potential confounders were sociodemographic and crash characteristics.Results Intense mind wandering (highly disrupting/distracting content) was associated with responsibility for a traffic crash (17% (78 of 453 crashes in which the driver was thought to be responsible) v 9% (43 of 502 crashes in which the driver was not thought to be responsible); adjusted odds ratio 2.12, 95% confidence interval 1.37 to 3.28).Conclusions Mind wandering while driving, by decoupling attention from visual and auditory perceptions, can jeopardise the ability of the driver to incorporate information from the environment, thereby threatening safety on the roads.

IMPORTANCE A proportion of patients experience long-lasting symptoms following mild traumatic brain injury (MTBI). The postconcussion syndrome (PCS), included in the DSM-IV, has been proposed to describe this condition. Because these symptoms are subjective and common to other conditions, there is controversy whether PCS deserves to be identified as a diagnostic syndrome. OBJECTIVE To assess whether persistent symptoms 3 months following head injury are specific to MTBI or whether they are better described as part of posttraumatic stress disorder (PTSD). DESIGN, SETTING, AND PARTICIPANTS We conducted a prospective cohort study of injured patients recruited at the adult emergency department of the University Hospital of Bordeaux from December 4, 2007, to February 25, 2009. MAIN OUTCOMES AND MEASURES At 3-month follow-up, we compared the prevalence and risk factors for PCS and PTSD. Multiple correspondence analyses were used to assess clustering of symptoms and their associations with the type of injury. RESULTS We included 534 patients with head injury and 827 control patients with other nonhead injuries. Three months following the trauma, 21.2% of head-injured and 16.3% of nonhead-injured patients fulfilled the DSM-IV diagnosis of PCS; 8.8% of head-injured patients fulfilled the diagnostic criteria for PTSD compared with 2.2% of control patients. In multivariate analysis, MTBI was a predictor of PTSD (odds ratio, 4.47; 95% CI, 2.38-8.40) but not of PCS (odds ratio, 1.13; 95% CI, 0.82-1.55). Correspondence analysis suggested that symptoms considered part of PCS behave similarly to PTSD symptoms in the hyperarousal dimension. None of these 22 symptoms showed any pattern of clustering, and no clear proximity with head or nonhead injury status could be found. CONCLUSIONS AND RELEVANCE Persistent subjective symptoms frequently reported 3 months after MTBI are not specific enough to be identified as a unique PCS and should be considered part of the hyperarousal dimension of PTSD.