To wait or not to wait? Improving results when interviewing intoxicated witnesses to violence

Witnesses to violent crimes are often alcohol intoxicated, but few studies have investigated the impact of alcohol on witness reports. This study investigated how alcohol intoxication and time of interview affected reports of intimate partner violence (IPV). One hundred thirty six healthy men (N = 66) and women (N = 70) were randomized to an alcohol group (0.8g/kg for men, 0.75g/kg for women) (N = 70) or control group (N = 66), given juice. Participants consumed drinks in a laboratory setting before they witnessed an IPV scenario. Fifty percent of the intoxicated and sober participants were interviewed ten minutes after viewing the film and all participants were interviewed one week later. For the analyses, participants in the alcohol group were divided into two groups (moderately/highly intoxicated) based on their BAC-level. Ten minutes after viewing the event, highly (BAC = 0.08-0.15) intoxicated witnesses gave shorter, but as accurate, reports as moderately intoxicated/sober witnesses. All witnesses gave shorter and less accurate reports one week later compared to immediately after. However, an immediate interview increased completeness one week later. In general, time and high intoxication made witnesses give less detailed accounts of actions and verbal information, but not of objects. Highly intoxicated witnesses reported less actions and verbal information in all interviews, while information regarding objects was reported to a similar extent. At the present BAC-level, it is beneficial to conduct an immediate free recall interview with intoxicated witnesses to obtain a maximum amount of correct information and minimize the negative effect of time.