Identifying drunkenness in the night-time economy

Background: Prohibiting the sale of alcohol to intoxicated patrons by licensees and their staff requires definitions of drunkenness. Aim: To assess the relationship between blood alcohol concentration (BAC) and indicators used in field sobriety tests putatively associated with intoxication. Design, participants, setting, material and methods: A random sample of 314 female and 579 male city centre drinkers. Surveyors scored respondents' and non-respondents' gait, eyes and speech for signs of drunkenness as well as their drunkenness on a 10-point Likert scale. Breath analysis was used to determine respondents' BAC. Findings: Combinations of slurred speech, staggering gait and glazed eyes significantly predicted levels of BAC with a staggering gait indicating highest levels of intoxication. Conclusions: Subjective ratings of drunkenness by trained observers corresponded with BAC. Transition BACs denoting observable behaviour change associated with intoxication have been identified. Observations of gait, combined with assessment of slurred speech should be the basis of estimates of drunkenness.