Investigating the neurobiology underlying alcohol hangover: a translational approach

Abstract

Alcohol hangover is a common outcome of alcohol consumption leading to cognitive impairment, reduced productivity and increased accidents. Despite negatively impacting daily functioning, the biological mechanism of hangovers is not fully understood. This thesis aims to investigate the association between hangover behaviours and underlying brain pathology, focusing on the role of inflammation, using animal models as well as healthy volunteers. The effect of alcohol hangover on the cognitive performance of healthy volunteers will also be explored.

Using a model in mice the hangover period (8-12 hours) was associated with reduced locomotion and increased anxiety behaviours assessed using the open-field test. These symptoms were associated with an increase in inflammatory mediators in both the brain and periphery in addition to the activation of microglial cells. After establishing the model, different alcoholic beverages designed to lack hangover effects were investigated, revealing that diminished hangover behaviours were associated with a reduced inflammatory response.

The cognitive, emotional, psychomotor impairments, motivation to drink and changes in inflammatory factors (assessed in saliva) were then investigated in healthy volunteers experiencing hangover. This assessment was a naturalistic study conducted remotely via video chat. The results showed that hangover impaired performance in motor control, choice response time and sustained attention tasks but was not related to levels of inflammatory factors in the saliva.

During this thesis, the COVID-19 pandemic took place, with the consequent restrictions. This provided an opportunity to investigate the impacts that these restrictions had on mental health, alcohol consumption and motivation to drink, using an online self-report survey. Results demonstrated that 60.1% of respondents decreased and 23.2% increased their alcohol consumption during lockdown. Increased alcohol consumption was associated with greater anxiety and depression levels and ‘drinking to cope’ with COVID-19 restrictions.

This thesis highlights the association between hangover and cognitive impairment. It also demonstrates the link between hangover symptomology and inflammation. These associations could form the basis of future investigations which aim to mitigate the toxicities, cognitive impairments, and poor mental health outcomes related to alcohol hangover.