Psychologists have discovered a new genetic link between impulsivity and teenage binge-drinking. Researchers at the University of Sussex, working as part of a team of researchers from across Europe, made the discovery which is published in the journal Frontiers in Genetics.
Professor Dai Stephens from the School of Psychology at the University of Sussex said:
"Alcohol and drug abuse are well documented as being major public health issues in today's society. By uncovering a particular gene that links impulsive behaviour with binge-drinking we may be an important step closer to understanding why some young people face a struggle to control their urges to engage in risky behaviour like binge drinking.
"We have identified a variant of a specific gene, called KALRN, which is seen in teenagers who act impulsively and also binge-drink. This link is interesting as it suggests that people can be predisposed to impulsive behaviour, and perhaps also to early-life alcohol abuse. If we can understand how these gene variations predispose people to impulsive behaviour, we may be able to help control binge-drinking and other disorders linked to impulsivity, like drug addiction and ADHD."
Dr Yolanda Peña-Oliver, the postdoctoral researcher who carried out the research under Professor Dai Stephens' supervision, said:
"These results provide an insight into the possible neurobiological and genetic determinants of impulsivity and alcohol abuse. The KALRN gene codes for a protein called Kalirin. Kalirin is essential to the development of the nervous system, especially the formation of dendritic spines that are important for the ability of nerve cells to communicate with each other. Interestingly, it has also been associated with other impulsivity-related disorders, like ADHD."
How the research was conducted:
The researchers already knew that there was a link between impulsivity and a lack of control in drug and alcohol abuse, and that genetic factors contribute to addictions. But it is scientifically difficult in human studies to identify which particular genes contribute to impulsive behaviour and binge-drinking. By first studying impulsivity in mice - by measuring how good they were at waiting for a reward - and cross referencing the findings with an international database of genetic information, the team were able to narrow down the search for genes that might have a role to play in human impulsivity.
The study then looked at 1400 teenagers who also took part in a major survey about drinking and drug-taking habits. The teenagers were asked to respond to cues in order to receive a reward, and underwent fMRI scans as they did so. They were scored for their impulsivity, i.e., their inability to wait for the reward. When their results were checked against their DNA profiles, the researchers found that many of the same genes they had identified in mice were also associated with the level of impulsivity in the teenagers.
The brain mechanisms contributing to impulsivity in the teenagers were identified by the degree to which one part of the brain, the ventral striatum, was activated while they were waiting for the reward. Variations in one gene in particular - KALRN - were associated with both impulsivity and with a tendency to binge drink. The gene, KALRN, is involved in efficient connections between nerve cells.
Professor Dai Stephens supervised the research of Yolanda Pena-Oliver while she was at the University of Sussex. Dr Pena-Oliver is now at the University of Cambridge.
No mice or teenagers were given alcohol as part of this study.
The research was funded by a European Commission grant. The 1400 teenagers were part of a major European research project, called 'IMAGEN', which is investigating mental health and risk-taking behaviour in teenagers.
Mouse and Human Genetic Analyses Associate Kalirin with Ventral Striatal Activation during Impulsivity and with Alcohol Misuse. Yolanda Peña-Oliver, Fabiana M. Carvalho, Sandra Sanchez-Roige, Erin B. Quinlan, Tianye Jia, Tom Walker-Tilley, Stuart L. Rulten, Frances M. G. Pearl, Tobias Banaschewski, Gareth J. Barker, Arun L. W. Bokde, Christian Büchel, Patricia J. Conrod, Herta Flor, Jürgen Gallinat, Hugh Garavan, Andreas Heinz, Penny Gowland, Marie-Laure Paillere Martinot, Tomáš Paus, Marcella Rietschel, Trevor W. Robbins, Michael N. Smolka, Gunter Schumann, David N. Stephens for the IMAGEN Consortium Frontiers in Genetics. DOI:10.3389/fgene.2016.00052. Published online 07 April 2016.