Comparisons were made between outpatients using various benzodiazepines and an individually age and sex matched control group with regard to simulated driving (lateral position variation, brake reaction time, speed), simple reaction time, choice reaction time and short term memory. The patients exhibited greater individual speed variations in simulated driving, and impaired performance regarding simple reaction time and memory. No other behavioural differences were found. No effects on behaviour due to a small alcohol dose (0.40 g pure alcohol/kg body weight in men and 0.36 g pure alcohol/kg body weight in women) were discernible. BAC was just below 40 mg percent in the laboratory tests and about 25 mg percent in the simulator runs. Subjectively, a number of differences appeared between the two comparison groups. The patients reported higher levels of anxiety and depression, and lower wakefulness and well-being. Certain effects due to alcohol were noticeable with regard to subjective measures; a higher degree of confusion, tiredness and depression, and lower well-being. As regards tiredness, the patients seemed to be affected by alcohol to a slightly greater extent than the control group. Prior to drinking alcohol, four benzodiazepine users and two control persons were judged on the basis of outward signs to be affected by drugs or alcohol. No relationship between dosage and performance was detected. There was however a tendency for lateral position variation to increase with increased dosage. For brake reaction time, short term memory and choice reaction time, there were similar but weaker tendencies. Perceived depression and confusion increased with increasing dosage. The results do not give any clear indication that persons on prescribed benzodiazepine medication would constitute a significant traffic safety problem. A single dose of diazepam 5 mg had no clear effects on the control persons with regard to either behaviour or subjective measures. (A
Abstract