Alcohol induced cognitive impairment in a field setting

Abstract

A number of variables have been recognized as determinants of drug response. These are both pharmacological, such as blood alcohol concentration, and nonpharmacological, like the environment in which the drug is taken. Ethanol impairs cognitive and psychomotor performance on a wide range of abilities and there has been much research into the mechanisms of alcohol impairment but surprisingly little research done in the field. We investigated the effect of alcohol on individuals’ cognitive performance in a natural setting; pubs and bars in the city centre. Seventy healthy volunteers (19 – 55 years), who had bought and consumed their own alcohol in the premises, completed a short questionnaire and a battery of cognitive tests and mood measures; administered on a mobile phone. Subjects were breathalized after completion of the test battery, with a mean blood alcohol concentration (BAC) of 62.86 mg/100ml. There were highly significant effects of alcohol on errors and reaction times for most of the tasks and the mood measures. Splitting the population into low and high alcohol groups (at the UK legal driving limit 80 mg/100ml) showed significantly higher error rates in the arrow flanker test, maze tracking task and paired associates learning for the high alcohol group (mean 115.36 mg/100ml) compared to the low alcohol group (mean BAC 27.86 mg/100ml). Further work is needed in the field to directly compare patterns and levels of impairment found in natural settings to impairment found when in a laboratory setting.