Dr Karen Lorimer

The study from Glasgow Caledonian University, the University of Glasgow and Abertay University found that carrying out a second, delayed police interview with people who had witnessed an incident may yield more information than relying solely on details given directly by a drunk witness or victim at a scene.

Published in academic journal Frontiers in Psychology, the project was funded by Glasgow Caledonian University and involved 60 participants who were all assessed as heavy drinkers.

Study participants consented to watch a video of a serious car accident and half consumed alcohol after the event while the other half received a placebo drink.

Across two interview sessions — one conducted immediately and then another one-week afterwards — participants were asked to recall what they could remember about the accident.

While the alcohol and placebo groups remembered similar amounts of details, the alcohol group recalled more details and were also more certain about their responses when interviewed again after one week.

The researchers claim that the findings have implications for the criminal justice system as they show that witnesses and victims who drink after seeing an incident may benefit from a second interview with officers, which could add further details to the police investigation.

Glasgow Caledonian PhD researcher Benjamin Butterworth and Dr Karen Lorimer, in the Research Centre for Health (ReaCH), worked on the project with Dr Julie Gawrylowicz, of Abertay University’s Division of Psychology and Forensic Sciences, and Dr Christopher Hand, from the University of Glasgow.

Dr Lorimer said: “We are now seeing growing evidence that post-alcohol consumption testimony should not be dismissed, which has implications for various crimes including sexual violence.”

Dr Gawrylowicz said: “Given that a high number of crimes take place at or near places where alcohol is consumed, it is vital to study how to best support victims and witnesses who were drunk before, during, or after they witnessed a crime to ensure they can provide best evidence during police interviews.

“The prospect of potentially traumatic memories being experienced and processed in the days following an incident is also an area of concern in terms of the mental health of victims or witnesses, particularly amongst heavy drinkers where chaotic lifestyles may also be a factor.”

Dr Hand added: “This is the first study of its kind involving witnesses who are heavy drinkers in the first place, even without our alcohol/placebo intervention. “The findings have clear impact as to how we support witnesses.”