Chronic medical conditions and traffic safety: review of the California experience

Accidents among schizophrenic outpatients

A preliminary comparison of traffic, home, and work accident incidence was performed among 103 outpatient schizophrenic patients and an age matched sample of 123 controls. The number of motor vehicle drivers among schizophrenic outpatients was far less than among controls (70 of 103 versus 122 of 123; P = .00001). Among those who did drive, schizophrenic patients drove far less than controls (19 of 70 patients driving greater than or equal to 5,000 miles per year versus 81 of 122 controls; P = .0001). Patients also reported more accidents per miles driven than did controls, consistent with previous studies. Older patients reported more home accidents than did younger patients (five of eight for those over 55 years versus four of 95 for those less than 55; P = .0007); no similar effect was observed among controls. Schizophrenic outpatients may be at greater risk of motor vehicle accidents per miles driven than age matched controls; elderly patients may be at higher risk of home accidents as well.

Motor vehicle driving among diabetics taking insulin and non-diabetics

OBJECTIVE

To determine whether rates of road traffic accidents were higher in diabetics treated with insulin than in non-diabetic subjects.

DESIGN

Controlled, five year retrospective survey.

SETTING

Diabetic, dermatology, and gastroenterology outpatient clinics.

PATIENTS

596 Diabetics treated with insulin (354 drivers) aged 18-65 attending two clinics and 476 non-diabetic outpatients (302 drivers).

MAIN OUTCOME MEASURES

Rates of accidents in diabetic and non-diabetic subjects.

RESULTS

A self completed questionnaire was used to record age, sex, driving state, and rates of accidents and convictions for motoring offences among diabetic and non-diabetic volunteers. For the diabetic volunteers further information was obtained on treatment, experience of hypoglycaemia, and declaration of disability to the Driving and Vehicle Licensing Centre and their insurance company. Accident rates were similar (81 (23%) diabetic and 76 (25%) non-diabetic drivers had had accidents in the previous five years). A total of 103 diabetic drivers had recognised hypoglycaemic symptoms while driving during the previous year. Only 12 reported that hypoglycaemia had ever caused an accident. Overall, 249 had declared their diabetes to an insurance company. Of these, 107 had been required to pay an increased premium, but there was no excess of accidents in this group.

CONCLUSIONS

Diabetic drivers treated with insulin and attending clinics have no more accidents than non-diabetic subjects and may be penalised unfairly by insurance companies.

Type 1 diabetes and driving experience: an eight-year cohort study

The driving habits of 250 drivers with Type 1 diabetes were reviewed 8 years after a previous assessment. At least 45 patients had died and 18 patients could not be traced. A postal questionnaire of the 187 survivors elicited a response from 89%. Fifty-six patients (34%) still held an unrestricted driving licence, demonstrating that a significant proportion of diabetic drivers had not declared diabetes to the licensing authority and/or their motor insurer and continued to ignore the statutory regulations. Fewer patients held Heavy Goods Vehicle licences than 8 years previously. Twenty-four patients had ceased driving as their driving skills had diminished with advancing age and ill health. This was a voluntary decision by all but two patients whose driving licences had been revoked. Thirty-nine patients admitted to a total of 55 road traffic accidents since 1979; 9 accidents (16%) were attributed to hypoglycaemia. Although dependent on patients' honesty and the accuracy of recall, the disclosed accident rates of 4.9 per million miles driven for male drivers and 6.3 per million miles for female drivers are comparable to the accident rate of a non-diabetic driving population of similar age.

The aging driver. Medicine, policy, and ethics

With the graying of America, more older persons will be driving. Physiological changes associated with normal aging and diseases that commonly affect the elderly may compromise their ability to drive safely. Although all states have regulations governing driving licensure, few offer specific guidelines regarding older persons. Accordingly, much of the responsibility for determining medical competence to drive and counseling patients in this regard is left to physicians. Normal physiologic changes may limit sensory information, particularly visual, available to the driver. In addition, chronic diseases in older persons including coronary artery disease, dementia and other neurologic disorders, diabetes mellitus, and drug use may increase the risk of crashes while driving. Once the question of competence to operate an automobile has been raised, ethical dilemmas must be addressed regarding the benefit of continued driving for the individual versus the risk to that person and society as a whole. In this article, we review the medical grounds for determining competence to drive, discuss ethical implications, and report current legal regulations for physicians and aging drivers. Future directions and possible areas for further research are outlined.

Marijuana's effects on human cognitive functions, psychomotor functions, and personality

Marijuana is complex chemically and not yet fully understood, but it is not a narcotic. Like alcohol, marijuana acts as both stimulant and depressant, but it lingers in body organs longer than alcohol. Smoking marijuana can injure mucosal tissue and may have more carcinogenic potential than tobacco. Research has indicated that marijuana intoxication definitely hinders attention, long-term memory storage, and psychomotor skills involved in driving a car or flying a plane. Expectations and past experience with marijuana have often influenced results more than pharmacological aspects have. Marijuana has triggered psychotic episodes in those more vulnerable. Psychological and some instances of physiological dependence on marijuana have been demonstrated. As a psychoactive drug, marijuana surely alters mental functioning. Although it is possible that chronic use of marijuana produces irreversible damage to mind or brain areas, this has not been determined by research.

Comparison of the psychosocial effects of epilepsy and narcolepsy/cataplexy: a controlled study

A questionnaire survey compared the psychosocial effects of epilepsy in 60 patients without major organic pathology (selected cases with temporal lobe epilepsy or primary generalized epilepsy) with those of matched (duration of illness, sex) patients with narcolepsy/cataplexy and with those of age- and sex-matched controls. Comparing epileptic patients with controls, we confirmed the well-documented marked deleterious effects of epilepsy upon work, education, occupational and household accidents, recreation, personality, interpersonal relations, and other parameters. Comparisons of epileptic and narcoleptic patients, however, showed that, in general, persons with narcolepsy are even more psychosocially impaired. The narcoleptic patients showed greater frequencies of disease-attributed reduced performance at work, poorer driving records, higher accident rates from smoking, greater problems in planning recreation, and other significant differences. Rather dissimilar profiles of psychosocial impairment were found to characterize the two conditions, and these were largely understandable as a function of their symptoms. The only areas in which epileptic patients showed greater problems than those with narcolepsy were in educational achievement and in ability to maintain a driving license. Most of the intergroup differences remained significant even for smaller groups matched also for age. The somewhat greater psychosocial impact of narcolepsy appears to be due to the continuous excessive daytime sleepiness that persists between the diagnostic attacks, whereas persons with epilepsy are relatively alert between seizures.

Admission to hospital for road trauma in patients with diabetes mellitus

A total of 8623 patients admitted to hospital in Western Australia with a diagnosis of diabetes mellitus during 1971-9 were linked with hospital admissions for road trauma during the same period, and their admission rates compared with the whole population. Although there was no overall difference, there was a significant excess of admissions in diabetic men aged under 55, the excess being produced by those in control of a vehicle and pedestrians. There were smaller excesses in the same female age group and a corresponding deficit in older diabetics. The results are limited through being based on routinely collected data on hospital admissions both for diabetics and victims of road crashes but indicate that there is a real problem of road accidents among diabetics that should be more fully investigated with a population based study that would collect important additional information unavailable in this study.

Psychosocial predictors of accident/error rates in nursing studies: a prospective study

A prospective study of accident/error rates was carried out on thirty-one nursing students. Recent life changes and stresses, social support available to cope with this stress, depression, illness rate, and coping skills were measured at baseline. Five weeks later students recorded accidents suffered and errors made over a week long period. The number of life changes in the previous two years made over a week long period. The number of life changes in the previous two years and the amount of adjustment required to cope with these changes, together with the social support available to help cope with these events were the most powerful predictors of accident/error rate. Together they accounted for 70 per cent of the variance. Multiple regression equations for the outcome variables were calculated to study the best linear predictor combination. Depression and coping skills had poor predictor power. The implications of the findings for health care personnel are discussed. Steps to lower the accident/error rate in those at risk are outlined.

Driving and insulin-dependent diabetes

A survey of 250 patients with insulin-dependent diabetes (IDD) holding a full motor vehicle driving licence revealed that 107 (42.8%) had not declared IDD on their application for a driving licence. 70 of these (28% of entire group) claimed that they were unaware of the statutory requirements. There was no difference in the declaration-rate between men and women. 159 patients (66%) declared IDD for their motor insurance. 86 patients (34.4%) had had severe or frequent hypoglycaemia in the preceding six months, during which they had been driving regularly. 34 patients (13.6%) admitted involvement in a driving accident since commencing treatment with insulin, and 13 of these patients were aware that hypoglycaemia had been an important causal factor. The prevalence of diabetic retinopathy and cataracts was considerable, but few patients (2.4%) had severe impairment of vision in both eyes.

Mental illness and road traffic accidents

One hundred psychiatric patients were carefully matched with 100 physically ill patients and their driving records compared. The psychiatric patients were consuming far greater quantities of psychotropic drugs and included a larger number of alcoholics and heavy drinkers. During the six months before admission there were no significant differences between the two groups of patients with respect to accident and traffic code infringements. Apart from individual patients, drugs did not appear to be influencing the outcome in statistical terms. Alcoholics and heavy drinkers showed an increased lifetime accident liability. No specific psychiatric diagnosis was otherwise associated with increased accident rates. The majority of accidents reported were relatively trivial.

Traffic accidents caused by epilepsy

During a 10-year period, 203 traffic accidents were suspected of being caused by epilepsy; 155 of them definitely caused by seizures were selected for study. The seizures of 75% were psychomotor; in 12% the seizure was the first, and only 4% of the rest had reported that they had epilepsy when they applied for a license. Traffic accidents due to epilepsy were less serious than the "average accident". They involved another vehicle much less often, and they occurred more often outside rather than inside built-up areas. Accidents caused by epilepsy were rare--1/10,000 in the 10-year period. The characteristic features of the traffic accident due to epilepsy may be due to the "random" occurrence of seizures in traffic, and to the seizure-suppressing effect of increased vigilance in city traffic.

Driving record of medical and surgical patients

Records of accidents and driving violations for 3 yr. prior to hospitalization were obtained for 798 medical-surgical patients with active driver licenses. Results indicate that the accident involvement of medical-surgical patients is not significantly different from that of psychiatric patients or from that of a large random sample of male California drivers. With respect to driving violations, both patient groups had a significantly higher record of violations than the comparison group. High-accident involvement was associated with genito-urinary and respiratory disorders. The findings strongly suggest that accident risk may almost triple as the severity of medical-surgical symptoms increases to the point requiring hospitalization.