A new study led by researchers at King’s College London has found that adolescents with particular patterns of brain development report an increased frequency in drunkenness. The research was published today in JAMA Psychiatry.
Using brain imaging data collected from 726 healthy adolescents, the researchers analysed changes in the volume of grey matter and in the frequency of drunkenness from the age of 14 years to 19 years.
The results showed that those who experienced decreases in grey matter in the frontal and temporal regions of the brain over this five year period also showed an increase in how often they reported getting drunk.
Drunkenness is described as behaviours that indicate a strong intoxication, such as staggering when walking, not being able to speak properly, vomiting or not remembering what happened.
Adolescents were asked how often they experienced drunkenness in the last 12 months.
There is continuing debate about how much alcohol causes changes in brain structure in adolescents or if there is a path of structural development in the brain that influences behaviour, which may put certain adolescents at greater risk of drunkenness.
This new study puts into question previous interpretations of research in this area which suggest drunkenness has a harmful effect on the developing brain of healthy adolescents.
Its findings indicate that structural differences in the grey matter of some healthy adolescents could predispose them to certain behaviours which result in more frequent drunkenness. The study does not investigate changes in brain structure in adolescents who were drinking heavily.
The association between changes in grey matter in the brain over time and increased drunkenness in girls was particularly strong.
The research team also investigated the role of impulsivity and found that only boys showed an association between impulsivity and increased drunkenness, suggesting there may be independent developmental pathways leading to drunkenness for boys that is different from that in girls.
“Our research showed that, in this group of healthy European adolescents, brain changes in the frontal and temporal lobes might happen even before the onset of alcohol use.
This means that claims that teenage drinking will damage your brain are over-simplistic and do not reflect the complexity of the interactions between brain development and the environment.
In adolescents who are not drinking heavily, structural changes in the brain could in fact be a predictor of alcohol use and more research is needed to identify possible risk factors that could ultimately help characterise those individuals.”
Commented Professor Gunter Schumann from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London.
The study investigated the relationship between changes in the volume of grey matter in the brain, the experience of getting drunk and personality measures such as impulsivity and openness.
The data was sourced from the European Union-funded FP6 Integrated Project IMAGEN study which has collected MRI brain scans and data from healthy adolescents from the UK, France, Germany and Ireland at 14 years old, 16 years old and 19 years old. The follow-up at 19 years was funded by the Medical Research Council (MRC) and the German Federal Ministry of Research & Education (BMBF).
The relationship between heavy alcohol use and brain development in adolescents was not studied.
Brain regions where a decrease in grey matter between the ages of 14 and 19 years is associated with an increase in drunkenness frequency between 14 and 19 years Image is credited to King’s College London.
Huge developmental changes occur in the brain during adolescence and this is also the time when individuals tend to start substance use so there is a longstanding debate about the causality between brain development, drug use and mental disorders.
Our findings indicate that certain patterns of brain development can promote certain behaviours and, under given circumstances, this could result in an increased frequency of drunkenness.
To get a more precise overview of the role of brain development in substance use disorders, we would like to focus on the individuals with the most severe decreases in grey matter and monitor the onset of substance use disorders over time.” Said Dr Gabriel Robert from the IoPPN and the University of Rennes.
The research was published in JAMA Psychiatry. There were two co-lead researchers: Gabriel Robert from King’s College London and the University of Rennes 1, France and Qiang Luo from Fudan University, Shanghai.
Alcohol consumption is widespread in Western societies and occurs in many everyday life situations. It also occupies an important position among young people, particularly among students, where it is a key component of the so-called academic folklore (Wechsler & Nelson 2001).
Despite this ubiquity of alcohol consumption, leading most people to consider it a relatively harmless substance, the danger of excessive drinking habits has been recognized. Alcohol-related disorders, currently identified as the third risk factor for premature death by the World Health Organization (WHO), lead to 3 million deaths per year worldwide (WHO, 2016). Excessive alcohol consumption is thus considered a central public health problem (Nutt, King, & Phillips 2010).
The consequences of alcohol abuse and dependence have also been extensively explored in scientific research, which has mainly focused on long-term and chronic alcohol-related problems and shown, for example, cognitive (Stavro, Pelletier & Potvin 2013), emotional (Donadon & Osório 2014), interpersonal (Thoma, Friedmann & Suchan 2013), and cerebral (Bühler & Mann 2011) impairments related to alcohol dependence (as it is referred to in the DSM-IV) or severe alcohol use disorders (as it is referred to in the DSM-5). Aside from these consequences in severe alcohol use disorders, which have been largely documented, growing interest has recently been observed in the effects of alcohol consumption on non-alcohol-dependent young people.
Because nearly 2000 deaths per year in the United States are related to excessive drinking in students (Hingson, Zha & Weitzman 2009), research has started to explore whether excessive drinking leads to deleterious consequences and, if so, at which consumption threshold and frequency (Hingson, Zha, & White, 2017). Notably, some studies have suggested that the specific binge drinking pattern, characterized by repeated alternations between intense intoxication and withdrawal, could be associated with cognitive and emotional impairments (Stephens & Duka 2008).
The problem of binge drinking is widespread in youth: 40% of adolescents and young adults in Western countries presently report at least one binge drinking episode per month (e.g., Archie et al., 2012; Kanny et al., 2013). Other studies have found that this consumption pattern leads to cognitive and cerebral consequences (Hermens et al., 2013; Maurage, Petit & Campanella 2013a). It has even been suggested that binge drinking could be considered a first step toward severe alcohol use disorders (Bonomo et al., 2004). The main aim of this paper is therefore to identify the specific behavioral and cerebral impairments related to binge drinking habits in young adults through a critical review. It is focused on two main processes that have been identified as central to the understanding of alcohol-related disorders: executive functions and emotional processing.
Beyond this literature review, we also address five specific research avenues: (1) the specificity of the brain modifications observed in binge drinkers, (2) the nature of the relationship between binge drinking and behavioral/cerebral impairments, (3) the possible persistence of these impairments after the cessation of binge drinking habits, (4) the continuum hypothesis that links binge drinking with severe alcohol use disorders, and (5) the perspectives for prevention and intervention programs in binge drinking.
These research avenues have been identified on the basis of major perspectives or limitations underlined in the existing literature. It is therefore essential to offer a critical state-of-the-art discussion about these currently prominent issues related to the binge drinking research field.
Definition and Conceptualization of Binge Drinking
Binge drinking refers to an excessive but episodic alcohol consumption pattern, characterized by repeated alternations between large alcohol intakes and periods of abstinence. Nevertheless, to date, the conceptualization of binge drinking remains a matter of debate in the scientific literature, and no consensus has been reached regarding its definition. Two main proposals can, however, be identified in existing studies that target alcohol consumption (i.e., number of drinks consumed) or specific drinking pattern (i.e., computation of a binge drinking score).
The first classification that was proposed to capture binge drinking is based on the number of drinks consumed on one occasion, commonly recognized as the 5/4 measure (i.e., 5 alcohol units for men, 4 for women; Wechsler & Nelson 2001; Labhart et al., 2018). Such an approach has been widely used in epidemiological and public health research (e.g., Kanny et al., 2013). This proposal was further specified through the calculation of the blood alcohol concentration (BAC) level.
Specifically, the National Institute on Alcohol Abuse and Alcoholism (NIAAA, 2004) describes binge drinking as an alcohol consumption pattern leading to a BAC level of 0.08 g/dL, typically observed after four (for women) or five (for men) alcohol drinks over a period of 2 hours. To be considered binge drinkers, individuals have to present such a consumption pattern at least once a month.
Although focusing on the BAC level offers an initial objective definition, these quantities should take into account national differences (e.g., an alcohol unit contains 8 g of pure ethanol in the United Kingdom, whereas it contains 10 g in most European countries and 14 g in the United States). Another potential shortcoming of this definition is that it does not focus on the frequency of drinking habits, which is known to be a key variable in explaining the emergence of neurological consequences and alcohol use disorder.
Second, some authors have suggested that binge drinking should be described in reference to the drinking pattern rather than to alcohol consumption per se (Townshend & Duka 2002). This approach appears to be particularly well adapted to the exploration of drinking among people who consume alcohol in large quantities but in an irregular pattern (i.e., binge drinkers), which might not be detected with the NIAAA definition.
The computation of a binge drinking score was thus proposed, based on (1) consumption speed (i.e., number of alcohol units consumed per hour), (2) number of drunkenness episodes (drunkenness being defined as reduced ability to speak clearly, loss of coordination, and nausea), and (3) percentage of drunkenness episodes (i.e., ratio of drunkenness episodes to the total number of drinking episodes) in the last 6 months. More precisely, the following formula has been proposed to compute a binge drinking score: [(4 × consumption speed) + number of drunkenness episodes + (0.2 × percentage of drunkenness episodes)].
This binge drinking score has been widely used in the literature (e.g., Bø et al., 2016a; Czapla et al., 2015; Kessler et al., 2013) and cutoff scores have been provided to differentiate non-binge drinkers from binge drinkers (Townshend & Duka 2005). However, these cutoff scores also depend on the quantity of alcohol contained in one unit. Typically, the initial studies that used this binge drinking score (Townshend & Duka 2002, 2005) were conducted in England, where an alcohol unit contains 8 g of pure ethanol. In these studies, a score higher than 23 indicated intense binge drinking, whereas a score lower than 17 characterized non-binge drinkers.
In Belgium, where an alcohol unit comprises 10 g of pure ethanol, adapted cutoffs have been proposed in accordance with other alcohol variables, such as number of doses consumed per occasion or consumption speed (e.g., Lannoy et al., 2017a): binge drinkers were thus defined as having a score higher than 17, whereas non-binge drinkers have a score lower than 13. Another advantage of the binge drinking score is that it indirectly takes into account enhancement-related motives (e.g., euphoria), which constitute strong predictors of binge drinking (e.g., Kuntsche et al., 2014).
Consideration of consumption speed and drunkenness allows one to target the motivational aspects of drinking (e.g., drinking a large amount to rapidly become intoxicated and thus feel the positive sensations associated with alcohol).
Definition of Related Alcohol Consumption Patterns
In this section, we briefly describe the different terms used to refer to excessive drinking among young adults that may be related to binge drinking, including hazardous drinking, heavy episodic drinking, and social drinking. Some of the studies that we review focus on these alcohol consumption patterns and describe them with the number of “binge drinking episodes” in a specific time frame, thus proposing a direct link with binge drinking.
According to the WHO, alcohol consumption ranges from hazardous drinking to physical dependence (Babor & Higgins-Biddle, 2001). Hazardous drinking refers to a repetitive pattern of alcohol consumption that leads to physical, mental, and social consequences. This drinking mode consists of the consumption of at least five (women) or seven (men) drinks per occasion at least three times per week. In the literature, the Alcohol Use Disorders Identification Test score is used to categorize individuals as hazardous drinkers (e.g., Palfai & Ostafin, 2003; Van Tyne et al., 2012), typically when they have a score higher than seven.
Heavy episodic drinking is defined by the NIAAA as a binge drinking pattern (at least four or five United States alcohol units consumed per occasion) that occurs more than once a week (NIAAA, 2004). In most studies, heavy drinking is used as a synonym for binge drinking, without necessarily representing a more frequent pattern of excessive drinking (e.g., Nederkoorn et al., 2009).
Social drinking is mainly related to the motivations underlying alcohol consumption and characterizes individuals who drink alcohol in social contexts. However, in the literature, this term is often used to refer to excessive drinkers (mostly according to weekly alcohol consumption, e.g., Townshend & Duka, 2001) but without a systematic evaluation of drinking motives or alcohol expectancies (Petit et al., 2012).
This section highlighted the various related concepts used to define excessive alcohol consumption habits in youth, particularly binge drinking. Most studies that focus on binge drinking use one definition or another, but combining these definitions to simultaneously consider the BAC level and the binge drinking score might lead to a more valid definition of specific binge drinking habits.
However, such a definition has to be considered in terms of large samples and different populations so that a better consensus can be proposed regarding its use. Despite this ongoing debate about definitions, many studies have explored the consequences of binge drinking during the last decades in order to specify the cognitive and cerebral impairments related to this drinking pattern.
In the next sections, we first review the behavioral results that show that binge drinking is related to large-scale executive deficits, and then describe the studies that used neuroscience techniques to determine the brain modifications observed among binge drinkers.
King’s College London
Franca Davenport – King’s College London
The image is credited to King’s College London.
Original Research: Open access
“Association of Gray Matter and Personality Development With Increased Drunkenness Frequency During Adolescence”. Gunter Schumann et al.
New England Journal of Medicine doi:10.1001/jamapsychiatry.2019.4063.