Mental Health and Driver Behaviour

In this excerpt, from our white paper ‘Improving Driver Well-being: a Guide for Managers’, Dr Lisa Dorn looks at mental health and its impact on driver behaviour.

What is mental health?

It is important to note that mental health is not just the absence of mental disorder. Symptoms reported by people with a diagnosable mental health condition such as anxiety and depression can be experienced by anyone. Everyone is on a “spectrum of well-being” as there are periods in our lives when symptoms can emerge due to a whole range of different circumstances. The World Health Organisation defines mental health as “…a state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community.”

The impact of mental health conditions in the workplace is significant, with 15.4 million working days lost as a result of stress, anxiety or depression every year. This represents a conservative estimated cost to the UK economy of £5.2 billion per year (HSE, 2021). In addition, there are consequences in terms of poor productivity and human error, increased sickness absence, high staff turnover and poor performance. Fleet managers are also concerned about whether stress, anxiety and depression may increase the risk of crash involvement.

Depression, Stress and Driving Behaviour

Depression is a form of mood disorder characterized by feelings of sadness, hopelessness, or misery. Individuals report a loss of interest in nearly all activities and suicidal thoughts or self-blame may be present and it can interfere with an individual’s ability to perform routine daily functions (Charlton et al. 2004). Depression is the most common psychiatric disorder affecting the population. About 1 in 4 people experience a mental health problem of some kind each year in England according to Mind, the mental health charity. Furthermore, 1 in 6 people report experiencing a mental health problem in any given week.

The impact of depression on the ability to drive safely can be significant. In experimental studies using on-the-road performance or simulation, depressed drivers encounter difficulty with reaction time, divided attention, reaction to changing speeds when following another vehicle, and weaving within lane. These difficulties are likely to impact drivers’ risk of collision (Wickens, 2014). At the extreme, it has been reported that there are over deaths by suicide taking place on UK roads every year (PACTS, 2017). One of the most common symptoms of depression is that sleep patterns can be disrupted. Dai et al (2020) reported that stress caused by the pandemic led to sleep related problems.

Depression-related sleep problems can lead to fatigue behind the wheel, especially when driving on long shifts. Anxiety is a diverse and complex experience. It can be considered a continuum, ranging from feeling mildly anxious through to panic attacks. Studies have shown that public health emergencies, such as the severe acute respiratory syndrome (SARS) and the 2009 H1N1/influenza A epidemics, caused acute stress responses in people including fear, anxiety and anger (Carmona et al, 2016). Stress also affects sleep, including sleep– wake patterns (Sanford et al, 2014). Stress can lead to worries about what’s going on in your life and reduce the ability to concentrate and identify and respond to hazards. About 20% of drivers aged between 55–72 yrs have reported mild driving anxiety and 5.5% reporting moderate to severe anxiety (Taylor et al, 2011).

Anxiety can lead to a reluctance to drive among some people and even driving phobia (Taylor et al, 2002). Increased scores on a measure of depression-anxiety demonstrated than the presence of an anxiety or mood disorder nearly doubles the risk of a crash (Wickens et al, 2013) The first studies of psychological stress and driving risk found that diagnosed drivers were more than twice as likely to be involved in crashes or involved in driving offences than those who were not under such stress (Waller, 1965). In an acute untreated phase of anxiety, people can suffer from diminished cognitive abilities, an inability to concentrate and reduced reaction times. Studies of drivers involved in fatal crashes when compared with a control group, have found that psychopathology, in the form of suicidal, paranoid and depressive thoughts, was markedly more present for those drivers involved in crashes (Selzer et al, 1968). Social stress defined as personal conflict, financial stress or acute upset preceding a crash were commonly found.

Download ‘Improving Driver Well-being: a Guide for Managers’.