Adolescent drinking could be driven by altered DNA
Altered DNA in a gene linked to impulsive behaviour could be a risk factor for adolescent drinking, according to new research led by the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London.
Published today by the American Journal of Psychiatry, this study provides the first evidence for an epigenetic marker associated with alcohol consumption and brain activity during behavioural control.
Epigenetic changes affect the expression or activity of genes without changing the underlying DNA sequence – they are believed to be one mechanism by which the environment can interact with the genome. Crucially, epigenetic changes are potentially reversible and may therefore provide targets for the development of new therapies.
Researchers examined an epigenetic biochemical change in methylation of the DNA of the PPM1G gene. Pairs of Finnish identical twins, one twin with alcohol problems at ages 18 and 24 and one twin without this problem, showed increased methylation in the problem-drinking twin.
In a confirmatory sample of 14-year-olds, those with similar changes in the PPM1G gene were likely to escalate their alcohol drinking over the next two years. The epigenetic change in PPM1G was also associated with higher ratings of impulsivity at age 14, according to Professor Gunter Schumann of the IoPPN and colleagues from the IMAGEN Consortium. Both early escalation of drinking and impulsiveness are risk factors for future alcohol use disorders.
The study found that methylation of PPM1G may influence behavioural inhibition by altering activity in an area of the brain which integrates neural signals necessary for behavioural control.
Professor Gunter Schumann said: ‘Epigenetic changes such as those observed in our study could increase impulsivity and make adolescents more inclined to engage in excessive drinking. Highlighting risk factors such as these is the first step for designing prevention and treatment interventions for alcohol addiction.’
‘Environmental factors associated with alcohol use are poorly understood, so it would be intriguing to examine them more comprehensively and identify those associated with PPM1G methylation’, he added.
The study, presented today at the Annual Meeting of the American Psychiatric Association in Toronto, is part of the IMAGEN Consortium led by Professor Schumann and funded by the European Union with additional funding from the UK Medical Research Council (MRC). The consortium brings together scientists across Europe to carry out neuroimaging, genetic and behavioral analyses in 2,000 teenage volunteers in Ireland, England, France, and Germany. The IMAGEN project aims to investigate the roots of reinforcement behaviour and mental health in teenagers.
Notes to editors
Schumann G et al (2015) ‘Association of Protein Phosphatase PPM1G With Alcohol Use Disorder and Brain Activity During Behavioral Control in a Genome-Wide Methylation Analysis’. American Journal of Psychiatry
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