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Margaret Harris has been a Medical Adviser at the Driver and Vehicle Licensing Agency for 10 years. She held previous posts in general practice and as a Senior Registrar in Psychiatry at Cefn Coed Hospital, Swansea. Correspondence: Bolgoed Newydd Farm, Heol y Barna, Pontlliw, Swansea SA4 1HG.
In the interest of road safety, driving license holders who suffer from a medical condition likely to affect fitness to drive must notify the Driver and Vehicle Licensing Agency (DVLA) and not drive. The Secretary of State for the Environment, Transport and the Regions (of the Department for the Environment, Transport and the Regions, DETR) has the responsibility, via his Medical Advisers at the Drivers Medical Unit of the DVLA, to ensure that all licence holders are fit to drive.
This paper explains the implications for road safety of psychiatric disorders in drivers. The medical standards discussed are based on legal requirements.
| Importance of medical conditions to road safety |
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| History of driver licensing |
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| Legal basis of fitness to drive |
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| Box 1. Prescribed Disabilities Group 1 Epilepsy of any type within the past year Inability to read a car number plate at 20.5 m Any sudden disabling attack of giddiness or fainting Severe mental disorder Alcohol or drug misuse, whether or not it amounts to dependency Group 2 (in addition to Group 1) Insulin-dependent diabetes Liability to epilepsy, defined as having had an attack or treatment for epilepsy within the past 10 years Inability to meet the eyesight standards: a visual acuity of not worse than 6/9 in the better eye; 6/12 in the worse eye un-corrected; and not worse than 3/60 in each eye uncorrected.
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The standards for vocational (Group 2) drivers are very high. Professional drivers spend up to a whole working week in their vehicle, which may weigh up to 39 tonnes or carry many passengers. An accident involving such a vehicle could put many people at risk.
| Application of the law |
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Licence holders' responsibility
It is the licence holders' legal responsibility to notify the DVLA if they have a medical condition that may affect safe driving: failure to do so and giving false information constitute an offence. There are, in addition, insurance implications.
Doctors' responsibility
The General Medical Council (GMC) has issued guidelines covering situations in which licence holders cannot or will not notify the DVLA of their medical condition (e.g. those with dementia or a psychosis). These have been published by the GMC (1995) and DVLA (2000). The Royal College of Psychiatrists (1993) has also issued guidance to psychiatrists on medical aspects of fitness to drive.
| Causes of accidents |
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The High Risk Offenders (HRO) scheme, a product of the Blennerhassett Committee, was piloted in the 1980s and became operational nationwide in 1991 (for details see DVLA, 2000). It was soon evident that, as a result of the scheme, heavy social drinkers became more responsible and stopped drinking and driving. There was less success with problem drinkers, who seemed less amenable to anti-drinking and driving publicity and education, and it was intended that these should be identified. Even in 1997, when road deaths were reduced to their lowest annual figure of 3500, alcohol was still considered directly responsible for 15%.
Although there has been an overall trend for the number of serious injuries and deaths to reduce considerably, minor injuries continue to increase, and these have a great socio-economic cost.
Human factors play a major role in RTAs, estimated at 95%; only 18% of RTAs are associated with road deficiencies and a negligible number with mechanical faults in vehicles. The major factors owing to human agency are speed, alcohol consumption and perceptual difficulties. Speed usually means going too fast for the prevailing conditions, and is a reflection of the driver's judgement. Cognitive errors, perceptual problems, misinterpretation of the actions of other road users, looking but not seeing, inattention and distractibility are the major human errors (Sabey, 1999). As can be seen, therefore alcohol aside cognitive or psychological difficulties are the major causes of accidents.
Driving is a complex skill, which is usually learned by practice at an early age. The technique of managing a vehicle's controls is, however, only the beginning. A new driver has to be adept at information processing. There must be sustained attention or vigilance, concentration and a good memory. Adequate visuo-spatial functioning is required, and indeed over 95% of the sensory input into driving is visual. There must be control over impulse and risk-taking. Judgement should be mature and unimpaired, with the ability to anticipate the actions of other road users. Problem-solving and hazard perception are necessary throughout the drive.
It can be appreciated, therefore, that many psychiatric disorders may present problems with driving (Metzner et al, 1993). It is for this reason that, although certain psychiatric disorders are listed in the medical standards, it is pointed out that the way in which an illness manifests itself in behaviour and cognitive function is far more important than the diagnosis itself. It is also true that drivers without a formal psychiatric diagnosis may be impaired. For example, a person may be extremely emotionally distressed, but never have had a psychiatric illness. The young man who, having just been told by his fiancée that the relationship was over, jumped onto his motorbike in tears and drove straight into the path of a bus was not ill. The immature, impulsive, excitement-seeking woman of 20 who enjoys alcohol and recreational drugs will be dangerous, but may not have a recognisable or treatable mental illness.
| Are people with psychiatric disorders dangerous drivers? |
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It has been estimated that 25% of drivers involved in accidents are impaired owing to alcohol, drugs, illness or emotional disorder (Cremona 1996).
Silverstone (1988) tells us that there is little evidence that those with schizophrenia are more dangerous than controls. However, suicide attempts at the wheel are worryingly high, and he describes a study in which 10% of accident drivers had suicidal ideation. He also quotes a study showing that patients with neurotic disorders, including anxiety states, have 50% more accidents than controls. His conclusion was that overall, patients with psychiatric disorders had a higher risk of RTAs than expected. The most dangerous were those with dementia, followed by hypomania and mania; severe depression and suicidal ideation, personality disorders and alcohol misuse are the other significant diagnoses.
Elkema et al (1970) found that male patients with a personality disorder had six times as many RTAs as controls.
Gibbons (1976) notes that most mental illnesses tend to reduce activity and interest, and therefore possibly the use of a car. This may lower the anticipated risk. Dangerousness was most likely in the acute phase, particularly in hypomania. However, he quotes evidence suggesting that a psychiatrically ill patient is far more dangerous as a driver before hospital admission and treatment than after it. He points out the unacceptable danger of suicidal thoughts in a driver, commenting that risk-taking may accompany the despair of depression. The risk is much greater if a driver has delusions or preoccupations related to motoring or other drivers. He ends by commenting that personality disorders in which aggression, impulsiveness, intolerance or frustration are exhibited are the most dangerous in drivers, and that indecision, preoccupation and poor concentration may occur in almost any psychiatric illness.
The incidence of driver suicides is probably underestimated. Ohberg et al (1997) describe a study undertaken in Finland between 1987 and 1991 in which a number of teams, each including a police officer, physician, vehicle engineer and road specialist, collected statistics covering the whole country. At least 5.9% of fatal driver accidents were suicides. Single-car accidents were less common than head-on collisions with a heavier vehicle. In 4% of cases, the crash led to the death of another person. The risk factors were youth (50%), stressful life events, psychiatric disorder, alcohol misuse and driving under the influence of alcohol. A significant number of drivers were, however, middle-aged sober men.
Anecdotal evidence comes to the DVLA via police reports (see Boxes 2 and 3![]()
). I conducted a brief analysis of the first 250 of just over 1000 police reports received in 1995, and the results are shown in Figs 1 and 2![]()
. Where illness or disability were implicated, psychiatric disorders constituted the largest single cause of accidents. Dementia was most prominent, but hypomania and suicide attempts at the wheel were not insignificant.
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| Box 2. Dementia in a 73-year-old male A 73-year-old man with dementia set off to visit his daughter. He quickly got lost and drove anti-clockwise around the M25 until he ran out of petrol. The police found him at 04.00 washing his car. It had three punctures and a large dent in the nearside door, which he could not explain. The police found him to be very confused and subsequent medical reports confirmed dementia: his licence was revoked.
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| Box 3. Schizophrenia in a 46-year-old male Following a report of a person acting strangely, a police officer found a man sitting in the driving seat of a car on a garage forecourt at Penrith, with the engine running. He told the officer that he had driven there from Birmingham to "get away from it all". He appeared very nervous and frightened and said that people were "out to get him". When asked who in particular, the man pointed to passing vehicles and said "Them". The police officer spoke to the man for over 30 min, during which time he learned that the man had been admitted to hospital four times under Section 2 of the Mental Health Act, the last occasion being 4 months previously. He was not taking any medication because it made him sleep. At one stage a vehicle stopped by the roadside and the man, seeing this, ducked down and said that they had come to get him. The officer was very concerned about his mental health and arrested him under Section 136 of the Mental Health Act. When asked if there was anything he would like to take from his car the man pulled a cricket bat from the passenger foot well. He held the bat in an aggressive manner and said "I will be needing this". The man was admitted to a psychiatric hospital and his driving licence was revoked.
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| Alcohol misuse or dependency |
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-glutamyl transpeptidase (GGT), aspartate aminotransferase (AST) and mean corpuscular volume (MCV). The medical standards have been laid down by the Secretary of State's Honorary Advisory Panel on Driving and Alcohol and Substance Abuse. About 40 000 HROs are assessed annually. Of these, 10% are found to have a history of recent alcohol misuse or dependency, and their licence application is either refused or restricted. | Box 4. Criteria requiring exclusion of alcohol misuse/dependency diagnosis in high-risk offenders More than two drink/driving offences in 10 years Alcohol level >2.5-times the legal limit Failure to give a specimen
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Others come to the notice of the DVLA because they have a history of alcohol misuse or dependency. This is now a Prescribed Disability under the Motor Vehicles (Driving Regulations) Act 1996, and the Secretary of State's Panel states that a person may not resume driving until free from alcohol misuse or dependency for a minimum of 1 year, because of the very high risk of relapse. There is much in the literature about the dangers of alcohol in drivers. There is a clear dose effect: as little as 30 mg/100 ml in the blood causes some impairment; at 50 mg/100 ml there is significant impairment and risk of accident; at 150 mg/100 ml, the accident risk is doubled; most social drinkers would be semi-conscious at 200 mg/100 ml, which is 2.5-times the legal limit.
| Substance misuse |
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| Dementia |
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With the help of consultant pyschiatrists, I undertook a small pilot study (unpublished) including 113 consecutive referrals with a diagnosis of dementia to psychogeriatric units in Wales. Of these only 17 were licence holders and 12 were currently driving. Therefore, only 10% of this group were actually driving. All the drivers had early-to-moderate dementia. The reasons for not driving were not studied, although it is known that many elderly drivers fail to renew their licences at 3-yearly intervals and have reduced access to a car. It is possible that the problem of dementia and driving may not be as large as suspected and further study is required.
Accurately assessing the fitness to drive of people with dementia is fraught with problems. An on-road practical test should be the only arbiter, but such assessments are not easy to arrange and require a valid driving licence. Private road systems do not allow full assessment of judgement, hazard detection and anticipation.
A battery of predictive table-top psychological tests would be a cost-effective method of screening drivers with a progressive neurological disease affecting cognitive function. However, developing such a battery is an illusive task. The tests should measure what science considers is the neurophysiological function of driving and require validation by driving assessment. They should be function-based and IQ-free. Unfortunately, the actual processes involved in driving are not yet fully understood, which makes the search for predictive tests even more difficult. Physical control is not the problem, as it is an over-learned skill resistant to decline.
The three systems found to be most predictive are the visualperceptual system, praxis and executive function. The latter is the most important. All psychological modalities involved in driving, including emotion and thought processes, are interlinked and brought together for action in the frontal lobes. Continuous monitoring of the environment, leading to the decision to transfer attention and make rapid judgements, also takes place in this region (McKenna, 1998).
How then can a clinician give an informed opinion about fitness to drive in dementia? Only with great difficulty in its early stages, but with far more certainty as the disorder progresses. Assessment of the activities of daily living is extremely useful: it is most unlikely that a person who cannot find the way to the toilet would be a safe driver.
Psychologists are often asked to assess whether patients can drive safely, but they are handicapped by not having a predictive set of tests or access to an on-road driving assessment. Clinical impression must therefore carry more weight than tests, and this is borne in mind by the Medical Advisers at the Drivers Medical Unit. Patients should be reminded to notify the DVLA as soon as they are diagnosed with dementia, and in the majority of cases the licensing decision will be made on clinical reports. In doubtful cases, on-road assessment is arranged, using the Driving Assessment Centres accredited by the Forum of Mobility Centres (for a full list see DVLA, 2000).
| Psychotropic medication |
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Side-effects can masquerade as symptoms of illness and vice versa, and it is sometimes very difficult to be clear about the cause of impairment. Often, the side-effects of psychotropic medication are individual, even idiosyncratic, and the longer a person is on a drug the less likely is significant impairment. It is wise to advise a person not to drive within 1 month of starting psychotropic medication or of increasing the dose. It is not possible to list here all drugs that are not acceptable in a driver. Drugs having anticholinergic side-effects should be avoided; these include tricyclic antidepressants and phenothiazines. The antihistamine effects of some antidepressant drugs may also cause drowsiness and care must be taken. Selective serotonin reuptake inhibitors, monoamine oxidase inhibitors and noradrenaline reuptake inhibitors have fewer side-effects and are safer. Most antidepressants and some antipsychotics reduce the epileptic threshold and may trigger epileptic attacks in vulnerable people (Harris, 1997).
Long-acting depot neuroleptics and the newer antipsychotic drugs can impair driving, but the sedative effect usually diminishes after about 3 months. Parkinsonian side-effects can be dangerous. Benzodiazepines are the most dangerous and are over-represented in drivers involved in RTAs. The interaction with alcohol of all drugs acting on the central nervous system will increase impairment and affect driving ability.
It is acknowledged that drivers with psychiatric illnesses are usually safer when well and on regular psychotropic medication than when they are ill. However, inadequate treatment or lack of compliance may render the driver impaired by both illness and medication. Special care should always be taken in prescribing psychotropic drugs in the elderly. It is good practice to ask the patient whether or not they drive and to advise accordingly.
| Risk assesment |
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The shortest period for which a driving licence can be issued is 1 year. Since an episode of psychiatric illness may be accompanied by loss of insight and an inability to realise that driving may be dangerous, it is essential to be confident that a person is not likely to relapse during that year. As insurance companies know, past accidents and convictions are the best predictors of future events. Some drivers are more high risk than others. Silverstone (1988) tells us that patients suffering from psychiatric conditions drive fewer miles per year than average. However, per mile travelled they have twice the number of accidents. Cremona (1996) also reminds us that the possible reason psychiatric disorders are not particularly associated with accidents is that those who have a severe psychiatric disorder may have limited access to a vehicle or voluntarily avoid driving. This will reduce the overall risk, and is an example of risk changing over time and in different situations. A risk is a probability: here, a prediction of a person's behaviour over time. Risk assessment is a difficult process, and in deciding fitness to drive it is based on thorough clinical assessment, addressing the questions "What is likely to happen, when and how?" (Maden, 1996). In this field, case law has defined probability: it is more than the barest possibility.
The risk factors used by the DVLA in assessing the safety of a driver are reflected in the questions posed to clinicians involved in the driver's care. These concern: the diagnosis; the history, including dates of remissions and relapses; the period of stability; compliance with medication and other treatments; intrusive symptoms; suicidal behaviour; cognitive impairment; side-effects of drugs; and alcohol and substance misuse. The risk that a person will pose to the road-using public is reflected in the duration of any temporary ban on driving and the subsequent periodicity of medical enquiry following the granting of a licence.
| Medical enquiry process |
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Medical enquiry may take some time, and during that period the driver still has a licence and therefore an entitlement to drive. One purpose of the At a Glance Guide to Current Medical Standards of Fitness to Drive (DVLA, 2000DVLA, 2000) is for the doctor involved in a patient's care to have some idea of the anticipated outcome of medical enquiry and to advise their patient accordingly. To drive when it is clear that the medical standards cannot be met would be foolish indeed.
The medical standards for drivers who have a psychiatric disorder have been in place since 1984, but two studies published in the mid-1990s (Humphreys & Roy, 1995; Thompson & Nelson, 1996) showed that psychiatrists were then largely unaware of them. It is important for medico-legal reasons that all doctors are aware of the medical standards and advise their patients accordingly.
| Conclusion |
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A licence holder or applicant has a legal duty to notify the DVLA of any medical condition that may affect safe driving. Subsequent medical enquiry is undertaken by the DVLA with the licence holder's consent. The Secretary of State of the DETR is responsible, through his Medical Advisers, for deciding whether a person meets the medical standards and is therefore eligible to hold a driving licence. If a licence is refused or revoked, the Medical Adviser explains the reason and the conditions to be met before a re-application can be accepted. The medical standards are continually revised by the Secretary of State's Honorary Medical Advisory Panels.
Medico-legal implications make it necessary for doctors and psychiatrists to be aware of the GMC guidance and also of the advice of the Royal College of Psychiatrists.
| Multiple choice questions |
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| References |
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Driver and Vehicle Licensing Agency (2000) At a Glance Guide to Current Medical Standards of Fitness to Drive. Swansea: DVLA.
Elkema, R. C., Brossen, J., Koshnick, R., et al (1970) A statistical study of the relationship between mental illness and traffic accidents: a pilot study. American Journal of Public Health, 60, 459469.
European Economic Community (1981) First EEC Directive. Brussels: EEC.
European Economic Community (1991) Second EEC Directive. Brussels: EEC.
General Medical Council (1995) Confidentiality. London: GMC.
Gibbons, T. C. N. (1976) Mental illness, personality and behaviour disorders. In Medical Aspects of Fitness to Drive (3rd edn) (ed. P. A. B. Raffle), pp. 3033. London: Medical Commission on Accident Prevention.
Harris, M. C. (1997) Psychotropic medication and driving. Psychiatry in Practice, 16, 57.
Humphreys, S. A. & Roy, L. (1995) Driving and psychiatric illness. Psychiatric Bulletin, 19, 747749.
Maden, A. (1996) Risk assessment in psychiatry. British Journal of Hospital Medicine, 56, 7882.[Medline]
McKenna, P. (1998) Fitness to drive: a neuropsychological perspective. Journal of Mental Health, 7, 9-18.
Metzner, J. L., Dentino, A. N., Godard, S. L., et al (1993) Impairment in driving and psychiatric illness. Journal of Neuropsychiatry and Clinical Neurosciences, 5, 211220.
Ohberg, A., Penttila, A. & Lonnqvist, J. (1997) Driver suicides. British Journal of Psychiatry, 171, 468472.
Raffle, P. A. B. (ed.) (1968) Medical Aspects of Fitness to Drive: A Guide for Medical Practitioners. London: Medical Commission on Accident Prevention.
Raffle, P. A. B. (ed.) (1976) Medical Aspects of Fitness to Drive: A Guide for Medical Practitioners (3rd edn). London: Medical Commission on Accident Prevention.
Raffle, P. A. B. (ed.) (1985) Medical Aspects of Fitness to Drive: A Guide for Medical Practitioners (4th edn). London: Medical Commission on Accident Prevention.
Royal College of Psychiatrists (1993) Psychiatric standards of fitness to drive large goods vehicles (LGVs) and passenger vehicles (PCVs). Psychiatric Bulletin, 17, 631632.
Sabey, B. (1999) Road Safety Back to the Future. Basingstoke: AA Foundation for Road Safety Research.
Silverstone, T. (1988) The influence of psychiatric disease and its treatment on driving performance. International Clinical Psychopharmacology, 3 (suppl. 1), 5966.
Taylor, J. (1995) Medical Aspects Fitness to Drive. London: Medical Commission on Accident Prevention.
Thompson, P. & Nelson, D. (1996) DVLA regulations concerning driving and psychiatric disorders. Psychiatric Bulletin, 20, 323-325.
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