19 March 2020
How does an alcohol hangover affect cognition?
We caught up with Lydia Devenney from Letterkenny Institute of Technology to find out why she chose CANTAB to assist her research into investigating attention, memory functioning, and mood in a natural setting with real‐life alcohol consumption levels.
It may seem logical that our ability to perform challenging tasks the morning after a night’s drinking is somewhat limited. However, our findings suggest that a cognitive blanket effect does not occur. Instead, the hangover affects our cognitive systems incongruously and therefore, a more comprehensive understanding of precise cognitive processes affected by a hangover is warranted. As we make strides to better our understanding, organisations should strive to update their safety regulations to account for the subsequent cognitive impairment after intoxication.
Global figures from census data of alcohol consumption in Ireland show that 11.46 litres of pure alcohol are consumed per person (over 15 years old) per year (World Health Organisation; WHO, 2018) - that’s 127.33 bottles of 12% wine or 498.26 568ml pints of Guinness! In the United Kingdom, 9.81 litres are consumed (WHO, 2018), adding up to 109 bottles of 12% wine or 426.52 pints of Guinness!
Absenteeism due to alcohol misuse in Northern Ireland alone is estimated to cost £33.1m (Department of Health, Social Services and Public Safety, 2011) and in the Republic of Ireland it is estimated to cost more than €41,290,805 (Mongan & Long, 2016). This indicates that the alcohol hangover affects the work of a large number of individuals in the Republic and Northern Ireland which in turn results in a considerable cost to the economy. What is more difficult to calculate is the cost of presenteeism. It is likely that loss of productivity, lateness, disputes with colleagues, accidents and poorly executed tasks at work due to alcohol related impairment the morning after a night’s drinking are a considerable expense. To fully understand the hangover’s impact on cognition and the dangers that it poses, exploration of the impact of hangovers on cognitive systems is required.
In the past, hangover research has yielded a series of inconsistent results which are likely to reflect methodological shortcomings and an under estimation of the complexity of the cognitive processes involved. As a result, the full impact of the alcohol hangover on cognitive functioning remains relatively under researched and overlooked. However, the Alcohol Hangover Research group (founded by Dr. Joris Verster) has accelerated our research collaborations and output, and today we stand in a much more favourable position to conduct hangover research and further our understanding of the ‘dreaded morning after’!
The study consisted of six tasks including the CANTAB’s Intra-extradimensional set shifting task and Spatial working memory task. At its inception hangover research involved an idiosyncratic set of tasks which created a challenging environment for direct comparisons. In recent years, tasks such as the Stroop and Eriksen’s Flanker task have become standardised in hangover research. Nonetheless, it is paramount that we now move beyond this to explore processes and procedures in depth to help understand why performance is affected. The extensive and detailed output measures from the CANTAB battery provide a great opportunity to do this. As well as this, it allows us to introduce a standardised task battery from which future hangover research can be compared, as well as allowing for direct comparisons of other recreational drug effects such as cannabis, ecstasy and cocaine.
As expected, when we compared hangover and control groups, we found significantly slower responses on Stroop and Eriksen’s Flanker task responses. Free recall was also impaired but no significant differences were revealed for divided attention or spatial working memory. As we often find differences in response time but not errors, the investigations of Intra-Extradimensional set shifting error variables from the CANTAB were relatively exploratory in nature. Intradimensional but not extradimensional errors differed significantly across hangover and control groups. Indeed, fewer errors were made by the hangover group than the no hangover group.
Intra-dimensional set shifting is thought to be less difficult than extradimensional set shifting as it does not involve a change in target dimensions. However, this task was not timed and one possible reason for the outcome is that hungover participants may have sacrificed time in order to improve response accuracy whereas non-hungover participants may have felt more confidence in the intra-dimensional trials and subsequently made more mistakes. Indeed, the speed-accuracy trade off may have resulted in more response caution in hungover participants as has been suggested by Grange, Stephens, Jones and Owen (2016) also. This may also account for the differences in response times but not errors that we often find in traditionally used tasks. We have since conducted research applying signal detection theory analysis to both address this speculation and help get to the nub of the decision making and attention to action processes at play during a hangover. We are hoping to prepare our article in the coming months- watch this space!
The Safety (implications)!
The evidence of impaired cognitive performance not only in this study but in those published in recent years warrants the consideration of hangover effects and the role they might have on human performance errors in safety critical environments. Currently, airline and seafarer companies, oil and gas rig operators, and medical surgery regulators consider the excretion of alcohol as a marker of the end of the effects of alcohol but the traditional ‘8-12 hour bottle to the throttle’ has become somewhat dated in light of our recent findings. It is therefore proposed that organisations (e.g. The Royal College of Surgeons, Federal Aviation Authority, Armed Forces, and International Transport Workers’ Federation) consider revising their codes of practice and implement rules which consider the time needed for a hangover to wear off once alcohol has left the system in order to both acknowledge and reduce the dangers of working the day after alcohol consumption.
Department of Health, Social Services and Public Safety (2011). Adult Drinking Patterns in Northern Ireland 2011. Central Survey Unit
Grange, J. A., Stephens, R., Jones, K., & Owen, L. (2016). The effect of alcohol hangover on choice response time. Journal of Psychopharmacology, 30(7), 654-661.
Mongan, D & Long, J (2016) Alcohol in Ireland: consumption, harm, cost and policy response. Dublin: Health Research Board.
World Health Organisation (2018) Global Information on Alcohol & Health. Levels of consumption. Retrieved from http://apps.who.int/gho/data/node.main.A1036
Lydia Devenney - Letterkenny Institute of Technology