Subjective and Objective Evaluation of Driving Behaviour in Depression

INTRODUCTION: Road traffic collisions and related casualties are a major issue for public health and society. Depression is characterized by mental, emotional and executive dysfunction, which may have an impact on driving behaviour. Among its symptoms sleep disturbance is very common. OBJECTIVES: The current study examined behaviour and attitude towards driving in a group of patients with depression and a group of controls, considering sleep disturbances. METHODS: Participants (patients N = 39 and controls N = 30) were asked to complete the Driver Stress Inventory (DSI) and Driver Behavior Questionnaire (DBQ). Afterwards, they were asked to drive on a driving simulator in a motorway scenario, and in urban and rural scenarios under low and high traffic load, all in good weather conditions. Driving simulator data included speed, lateral position (LP) and safety distance from the preceding vehicle. RESULTS: Gender, age and, to a lesser extent, body mass index influenced almost all variables. Patients with depression did not differ from the controls regarding driving behaviour as assessed through the DSI and DBQ questionnaires. Subjective fatigue was found to be positively correlated with aggression (β = 0.027, p = 0.005), dislike of driving (β = 0.036, p = 0.006), hazard monitoring (β = 0.046, p = 0.001) and traffic violations (β = 0.010, p = 0.020). On the driving simulator, patients maintained a longer distance from the preceding vehicle. Epworth Sleepiness Scale and Athens Insomnia Scale scores were positively associated with safety distance and with the Standard Deviation of LP, denoting lower ability to keep a stable vehicle track (β = 2.108, p = 0.003 and β = 0.047, p = 0.004 respectively). CONCLUSIONS: It seems that although certain symptoms of depression (insomnia, fatigue and somnolence) may affect driving performance, this effect is lessened by patients driving more carefully. There are parameters (age and sex) which influence driving behaviour and attitude similarly for both groups. KEY MESSAGES: • Patients with depression did not differ from controls regarding driving behaviour and attitude. • Patients seem to realize the effects of symptoms of depression on their driving ability and, consequently, drive more carefully.