Introduction:
Road traffic collisions and the 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 healthy controls, taking into account sleep disturbances.

Methods:
Participants (patients N=39 and controls N=30) were asked to complete questionnaires on driving stress (DSI) and behaviour (DBQ). Afterwards, they were asked to drive on a driving simulator in a motorway (MW) scenario, and under low (L) and high (H) traffic conditions in urban (U) and rural (R) scenarios, all in good weather conditions. Driving simulator data included speed, lateral movement (LPSD) and safety distance from the preceding vehicle.

Results:
Gender, age and, to a lesser extent, body mass index influenced almost all variables. The group of patients with depression did not differ from the control group 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 violations (β=0.010, p=0.020), as assessed by these questionnaires. 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 keeping a longer safety distance and with LPSD, denoting lower ability to keep a stable position (β=2.108, p=0.003 and β=0.047, p=0.004 respectively).

Conclusion: It seems that although certain symptoms of depression (insomnia, fatigue and somnolence) may affect driving performance, patients drive more carefully eliminating, thus, their impact. There are parameters which influence driving behaviour and attitude similarly for both groups (especially age and sex).

Keywords: depression, sleep disorders, road safety, driving, driving simulator

Other info: Maria Papadakaki, George Yannis, Dimosthenis Pavlou, Maria Basta, Joannes Chliaoutakis and Dimitris Dikeos