Acute psychosis and the risk of motor vehicle crash

ImportanceLimited empirical evidence guides fitness-to-drive decision-making following an episode of acute psychosis. ObjectiveTo evaluate the association between acute psychosis and subsequent crash risk. DesignRetrospective observational analyses using 20 years of population-based administrative health and driving data. We first assessed the association between psychosis and collisions using a case-crossover design, which controls for relatively fixed individual characteristics like personality, driving experience and routine driving habits. Next, we conducted a responsibility analysis which accounts for the changes in road exposure (miles of driving per month) that might occur after recent hospitalization. SettingBritish Columbia, Canada. ParticipantsDrivers with a police-attended motor vehicle crash, 2000-2016. ExposureA hospital stay for acute psychosis ending in the 6-week interval prior to crash. Main Outcomes and MeasuresThe case-crossover analysis examined crash involvement as a driver. The responsibility analysis examined driver responsibility for contributing to their crash. We used logistic regression with adjustment for potential confounders to evaluate associations between outcomes and recent acute psychosis. ResultsAmong 9842 crashes in the case-crossover analysis, a hospital stay for acute psychosis ended in 199 pre-crash intervals and in 147 control intervals, suggesting acute psychosis was temporally associated with subsequent crash (2.0% vs 1.5% of intervals; adjusted odds ratio (aOR), 1.32; 95%CI, 1.05-1.66; p=0.02). Among 819,348 drivers with a police-attended crash and determinate crash responsibility, 178 of 235 drivers with a recent hospitalization for acute psychosis and 440,543 of 819,113 drivers without recent psychosis were deemed responsible for their crash (75.7% vs 53.8%; aOR, 2.38; 95%CI, 1.75-3.24; p<0.001). ConclusionsThe 6-week interval following a hospitalization for acute psychosis is associated with increased odds of crash and increased likelihood of a driver being deemed responsible for contributing to their crash. More stringent temporary driving restrictions after an episode of acute psychosis might reduce crash risk. KEY POINTSO_ST_ABSQuestionsC_ST_ABSDoes a recent episode of acute psychosis increase a drivers likelihood of being involved in a motor vehicle crash? FindingsUsing population-based administrative health and driving data, investigators found that the odds of crash were higher in the first 6 weeks after a hospital stay for acute psychosis than during control periods. A responsibility analysis accounting for changes in road exposure found drivers were also more likely to be deemed responsible for contributing to their crash during this period. MeaningMore stringent driving restrictions in the first 6 weeks after an episode of acute psychosis might reduce crash risk.