The effect of minor tranquilizers on psychomotor performance

Review of Effects of Alcohol and other Licit Drugs on Driving-Related Performance

A review is presented of the effects of alcohol and licit drugs on performance related to driving. About 20% of persons of driving age use some licit drug, while a much greater percentage drink alcohol. Alcohol is used in combination with another licit drug by about 10% of persons of driving age. Alcohol is associated with about 50% of fatal traffic accidents, 30% of injury accidents and 10% of non-injury accidents. Other licit drugs, such as diazepam, are involved in about 20% of non-fatal accidents. Alcohol combined with other licit drugs, such as diazepam, is involved in about 10% of injury accidents.

The effects of alcohol on driving-related skills is relatively well-documented, but tests on the effects of other licit drugs present variable findings. There is some research which indicates additive or synergistic effects when alcohol is combined with other drugs.

Research to date on the effects of licit drugs alone, and in combination with alcohol, has many limitations. There have been comparatively few studies to test decision-making and perceptual-motor skills, such as used in driving or those involving actual driving tasks.

However, studies indicate that when combined with alcohol, some licit drugs lead to a deterioration in driving-related performance, but a need exists for further research involving more complex driving-related tests and actual driving situations.

Neurocognitive costs and benefits of psychotropic medications in older adults

Psychotropic medications are widely used in older adults and may cause neurocognitive deficits. Older adults are at increased risk of developing adverse effects because of age-related pharmacodynamic and pharmacokinetic changes. This article provides a comprehensive review of the undesirable, and at times beneficial, effects of psychotropic medications. The review covers a wide range of medications that impair executive function, memory, and attention, as well as a much smaller group of medications that lead to improved neurocognitive function. Some of the most commonly used psychotropic medications in older adults, namely, antidepressants, sedatives, and hypnotics, are among the drugs that most consistently lead to cognitive impairments. Medications with anticholinergic properties almost invariably lead to neurocognitive dysfunction, despite symptom improvement. The neurocognitive costs and benefits of psychiatric medications should be considered in the context of disease treatment in older adults.

Sedation and antihistamines: a review of inter-drug differences using proportional impairment ratios

The use of antihistamines (AHs) has until recently been associated with a number of undesirable side effects, the most troublesome of which is sedation. There are two aspects to sedation. The first, an objectively determined measure based on the results of psychometric tests from controlled trials, and the second, the subject's response to the administration of a drug. Since AHs are largely used in ambulant patients, a complete evaluation of sedation should be performed through standardised objective and subjective tests, shown to be sensitive to the central effects of AHs.An extensive review of the literature identified 76 studies of H(1) receptor antagonists in healthy volunteers, in which assessment of sedation was the primary objective. Results from studies published in peer-reviewed journals which employed a placebo condition as well as a positive internal control using a crossover design were analysed to determine the extent to which a particular antihistamine produced impairments on a battery of psychometric tests. The impairment index for each antihistamine was calculated and subsequently compared with the impairment index obtained for all other AHs.The calculation of this proportional impairment ratio enabled the sedative potential of an individual antihistamine to be identified relative to all other AHs and thus allowed the ranking of AHs with respect to their ability to cause impairments of cognitive and psychomotor function.Findings from this review clearly demonstrate that there are distinct classes of AHs with respect to their ability to impair cognitive function and psychomotor performance. Copyright 2000 John Wiley & Sons, Ltd.

Performance tests

This paper discusses the use of psychological performance tests to assess the effects of environmental stressors. The large number and the variety of performance tests are illustrated, and the differences between performance tests and other psychological tests are described in terms of their design, construction, use, and purpose. The stressor emphasis is on the effects of drugs since that is where most performance tests have found their main application, although other stressors, e.g., fatigue, toxic chemicals, are mentioned where appropriate. Diazepam is used as an example. There is no particular performance emphasis since the tests are intended to have wide applicability. However, vehicle-driving performance is discussed because it has been the subject of a great deal of research and is probably one of the most important areas of application. Performance tests are discussed in terms of the four main underlying models--factor analysis, general information processing, multiple resource and strategy models, and processing-stage models--and in terms of their psychometric properties--sensitivity, reliability, and content, criterion, construct, and face validity. Some test taxonomies are presented. Standardization is also discussed with reference to the reaction time, mathematical processing, memory search, spatial processing, unstable tracking, verbal processing, and dual task tests used in the AGARD STRES battery. Some comments on measurement strengths and appropriate study designs and methods are included.

Continuous reaction times in cerebral dysfunction

The Continuous Reaction Times (CRT) method was used to examine pharmacological, psychiatric, medical and neurological problems in clinical practice where a detailed neuropsychological examination with a test battery was not possible. Either 100 visual or 150 auditory stimuli were given within a period of 6 1/2 or 10 min respectively, and the patients were instructed to react as quickly as possible to every stimulus. The same CRT method was applied to heterogeneous groups of patients with cerebral dysfunction and control subjects. The results demonstrated that it was useful as a screening test for the presence of cerebral dysfunction and was especially sensitive to progressive diseases. Its discriminative power was equivalent to more sophisticated and complex psychological tests. Even if CRT is a valid and reliable method of testing cerebral affection, the neural background for the reaction time process is still unknown and the test did not distinguish between patients with right- or left-hemisphere lesions and was not influenced by the etiology of the disease. CRT is therefore considered a provisional method, suggestive only for the actual diagnostic procedures. Only when the patients have a well-defined diagnosis e.g. a diffuse cerebral affection caused by a drug or a metabolic disorder can CRT be recommended as a measure of the degree of lowered consciousness.

Adverse effects of antianxiety drugs

Antianxiety drugs, like other drugs used in psychiatry, can cause a wide range of adverse effects. Many physiological systems may be affected, but, as the main action of antianxiety drugs is on the central nervous system, this system is particularly vulnerable. All antianxiety drugs have the potential to produce untoward effects on higher cerebral functions, although the effect seen is also influenced by psychological and social factors. The most common effects is oversedation, which is a particular problem for the very young and the very old. It is also a serious problem for those who drive motor vehicles and may be a hazard when working in dangerous situations. Subjects are especially vulnerable when (a) antianxiety drugs are first introduced; (b) the dose is increased; and (c) these agents are taken in combination with alcohol and other drugs. Dependence on antianxiety drugs is well known, but only recently has it been recognised that dependence on benzodiazepines is a larger problem than previously realised. Other adverse effects are reviewed and summarised according to the system they predominantly affect. A review of this kind can easily give a biased impression of the dangers of antianxiety drugs; it should be made clear at the outset that many effects are rare, and in some instances a causal connection with the drug has not been established with certainty. Overall, benzodiazepines are the most widely used of all drugs and are remarkably safe-even when taken in massive overdoses. Some unwanted effects are readily preventable if antianxiety drugs are used with caution or avoided altogether in conditions where pathological disturbances of tissue sensitivity or drug disposition lead to exaggerated reactions. Particular care should be taken when prescribing these drugs for children and the elderly, and drugs that are not clearly essential for the well-being of the mother should be avoided during pregnancy and breast feeding. Antianxiety agents are grossly overprescribed. The frequency of occurrence of some adverse effects is therefore not so much a manifestation of the intrinsic toxicity of antianxiety drugs, but a reflection of their widespread use. Overprescribing and irrational prescribing also contribute to self-poisoning with these and other agents and to the cost of health services. The reasons for overprescribing are complex, but one contributing factor is the ready availability of effective antianxiety drugs.

Effects of benzodiazepines on psychomotor performance

1 The literature relating to the effects of benzodiazepines on psychomotor performance is critically reviewed. 2 The multiple and diverse psychomotor tests used are assessed according to their ability to demonstrate differences between drugs. 3 Three general conclusions are: (1) The speed with which simple acts of a repetitive nature are performed may be impaired by benzodiazepines. (2) learning and immediate memory will also be impaired. (3) there is relatively little indication that well established higher mental faculties are adversely involved.

Effects of terfenadine and diphenhydramine alone or in combination with diazepam or alcohol on psychomotor performance and subjective feelings

The effects of single oral doses of terfenadine, diphenhydramine and placebo, alone or in combination with diazepam or alcohol, on psychomotor performance and subjective feelings were evaluated in a double-blind, crossover study in 20 normal male volunteers. Terfenadine 60, 120 and 240 mg had no effect on psychomotor skills and subjective feelings, whereas diphenhydramine 100 mg slightly impaired certain features of psychomotor performance and severely worsened subjective feelings. Terfenadine 120 mg did not influence the adverse effects of oral diazepam 10 mg or of alcohol 0.75 g/kg on psychomotor performance and subjective feelings. In contrast, diphenhydramine 100 mg significantly enhanced these effects of diazepam and alcohol.

A comparison of the effect of imipramine, nomifensine, and placebo on the psychomotor performance of normal males

Imipramine (50 mg), nomifensine (50 mg) or placebo was administered early morning, late morning, and mid-afternoon to normal volunteers. The program of hourly tests included: the Digit Symbol Substitution, Perceptual Reversal, Time Estimation Test, and Simple and Complex Continuous Performances tests both of which required recognition of briefly exposed letters of the alphabet. It was found that relative to placebo or nomifensine, imipramine had a clearly detracting effect on most of the tests. Drowsiness was reported more often in the imipramine group than in the placebo and nomifensine groups combined.