“Heavy drinking in adolescence can lead to alcohol-related problems and alcohol dependence later in life,” said Carmen Van der Zwaluw, Ph.D., an assistant professor at Radboud University Nijmegen in the Netherlands, a corresponding author for the study.
“It has been estimated that 40 percent of adult alcoholics were already heavy drinkers during adolescence. Thus, tackling heavy drinking in adolescence may prevent later alcohol-related problems.”
Van der Zwaluw noted that the dopamine receptor D2 (DRD2) and the mu-opioid receptor (OPRM1) genotype are known to play a large role in the neuro-reward mechanisms associated with the feelings of pleasure that result from drinking, as well as from eating, having sex, and the use of other drugs.
“Different genotypes may result in different neural responses to alcohol or different motivations to drink,” she said. “For example, OPRM1 G-allele carriers have been shown to experience more positive feelings after drinking, and to drink more often to enhance their mood than people with the OPRM1 AA genotype.”
The researchers also looked at another element: Whether parents had set specific rules regarding alcohol consumption.
“Research has shown that, more than general measures of parental monitoring, alcohol-specific rule-setting has a considerable and consistent effect on adolescents’ drinking behavior,” she said.
Van der Zwaluw and her colleagues used data from the Dutch Family and Health study that consisted of six yearly waves, beginning in 2002 and including only adolescents born in the Netherlands. The final sample of 596 adolescents — half boys, half girls — were, on average, 14 years old at the beginning of the study and nearly 20 when the study was completed.
Saliva samples were collected in the fourth wave to enable genetic testing, she reported.
The teens were subsequently divided into three distinct groups of adolescent drinkers: Light drinkers, (58 percent); moderate drinkers (30 percent); and heavy drinkers (12 percent).
“Comparisons between these three groups showed that light drinkers were more often carriers of the OPRM1 AA ‘non-risk’ genotype, and reported stricter parental rules than moderate drinkers,” Van der Zwaluw said.
“In the heavy drinking group, the G-allele carriers, but not those with the AA-genotype, were largely affected by parental rules: More rules resulted in lower levels of alcohol use.”
Van der Zwaluw said that although evidence for the genetic liability of heavy alcohol use has been shown repeatedly, debate continues over which genes are responsible for this liability, what the causal mechanisms are, and whether and how it interacts with environmental factors.
“Longitudinal studies examining the development of alcohol use over time, in a stage of life that often precedes serious alcohol-related problems, can shed more light on these issues,” she said.
“This paper confirms important findings of others; showing an association of the OPRM1 G-allele with adolescent alcohol use and an effect of parental rule-setting. Additionally, it adds to the literature by demonstrating that, depending on genotype, adolescents are differently affected by parental rules.”
The bottom line is that parents can be a positive influence, Van der Zwaluw noted.
“This study shows that strict parental rules prevent youth from drinking more alcohol,” she said. “However, one should keep in mind that every adolescent responds differently to parenting efforts, and that the effects of parenting may depend on the genetic make-up of the adolescent.”
The study will be published in the March 2014 issue of Alcoholism: Clinical & Experimental Research.
Source: Radboud University Nijmegen