Previous research, both animal and human, has shown a relationship between a pleasurable response to sweet taste (sweet liking) and a genetic vulnerability to alcoholism among children of alcoholic fathers. Sweet liking, however, is insufficient by itself to predict alcoholism. New findings published in the September issue of Alcoholism: Clinical & Experimental Research indicate that alcoholic status can be predicted by a combination of two independent factors - sweet liking and novelty seeking.
"The results of this study confirmed our previous hypothesis that sweet liking is associated with genetic risk of alcoholism as measured by the paternal history of alcoholism," said Alexei B. Kampov-Polevoy, assistant professor of psychiatry at Mount. Sinai School of Medicine and first author of the study. "Then we tested the hypothesis that sweet liking can predict alcoholic status of an individual. Analysis showed that sweet liking by itself was not sufficient to predict alcoholic status of an individual … sweet likers were found among both alcoholics and non-alcoholic patients. Only a combination of sweet liking and elevated novelty seeking, as measured by the Tridimensional Personality Questionnaire, was sufficient to make such a prediction."
Kampov said that he and his colleagues decided to examine the role of "novelty seeking" in the equation because previous research has strongly implicated the presence of various elements of behavioral undercontrol – a personality trait that reflects an individual’s inability or unwillingness to inhibit behavioral responses in the face of impending punishment – in alcoholics.
"Novelty seeking has been frequently found to be higher in alcoholics, compared with nonalcoholic control subjects, as well as in patients with a familial form of alcoholism, compared with patients with nonfamilial forms of alcoholism," said Kampov. "It is believed that high novelty seeking causes early experimentation with alcohol and, as a result, higher lifetime rates of heavy drinking, alcohol abuse and dependence. In the past, there were several attempts to use novelty seeking as a predictor of alcoholism that failed because elevated novelty seeking can be also found in individuals who do not have any substance-abuse problems."
"It has been known for some time that sensation seeking or novelty seeking are associated with risk for alcoholism," agreed James C. Garbutt, professor of psychiatry at the University of North Carolina at Chapel Hill, "but that these are not the only traits associated with risk. It is intriguing that Dr. Kampov has some evidence linking this personality trait with sweet liking to indicate a higher risk for alcoholism."
Researchers examined 165 middle-aged patients admitted to a residential treatment program for alcohol, drug dependence, and/or interpersonal problems related to substance-abusing family members. All participants were given a routine medical examination. In addition, on the 24th day after admission, participants were given the Tridimensional Personality Questionnaire and a standard sweet-taste test, and evaluated for paternal family history of alcoholism.
"The main finding of this study is that two independent and presumably heritable traits, such as sweet liking and high novelty seeking, separately were insufficient to predict alcoholism in our sample," said Kampov. "However, if a person had both of these traits, he or she most likely was an alcoholic."
Kampov said this relationship is not surprising when one considers that both sweet liking and sensitivity to the rewarding effects of alcohol are related to brain function. "Children of alcoholics are reported to have a heritable dysfunction of the brain reward system that makes them super sensitive to the rewarding effects of alcohol," he said. "The same brain dysfunction causes the preference for stronger sweet solutions, or sweet liking. If such an individual has also high novelty seeking that causes early experimentation with alcohol, it significantly increases the risk of development of alcoholism."
"I think it is important to place this information into the context of what this means for a clinician and for a lay person," added Garbutt. "First, this method is not being proposed as a means to diagnose alcoholism. Rather, I would view the significance of the findings as contributing to our ability to understand subtypes of alcoholics and that, in turn, could have implications for treatment … although any treatment implications will require further study. Second, identifying factors that appear to be associated with alcoholism is the step required before testing them in a prospective study of individuals at risk for alcoholism to determine if these factors can indeed tell us something about who is at highest risk for alcoholism. Finally, understanding the biological/environmental bases of these two traits may allow us to better understand the pathophysiology and genetics of alcoholism."
Kampov concurs. "If confirmed by further research, these findings may lead to the development of a simple test that will allow clinicians to assess the risk of developing alcoholism of any given individual early in his or her lifetime," he said. "All parents are anxious to know about their child’s risk of developing alcoholism. Based on our findings, we may say that for children – especially boys – who prefer stronger sweet tastes and have signs of elevated novelty seeking, it is especially important to delay their first experience with alcohol, although the same advice is good for all children."
Garbutt said there are multiple questions that can be addressed in future research. "First, does sweet preference and personality profile truly predict increased rates of alcohol problems?" he asked. "To answer this question will require prospective studies, similar to what other researchers have done with sensitivity to alcohol consumption. Second, what are the genetic/environmental mediators of response to sweets? This will require the investigation of candidate genes as well as genetic linkage. Environmental contributions will be complex to sort out but we think there may be cultural/dietary factors present. Third, can sweet preference predict anything about treatment response to medications, and possibly psychosocial therapy as well? We are currently conducting a study of sweet liking as a predictor of response to naltrexone in alcoholism but no data has yet been analyzed. Fourth, if sweet liking is a marker for alcoholism, how does it interact with other markers/genes to lead to a complete understanding of the underlying risk factors for alcoholism and their implications for prevention and treatment? Answering the preceding is akin to finding the holy grail in our field."
Funding for this Addiction Science Made Easy project is provided by the Addiction Technology Transfer Center National Office, under the cooperative agreement from the Center for Substance Abuse Treatment of SAMHSA.
Articles were written based on the following published research:
Kampov-Polevoy, A.B., Eick, C., Boland, G., Khalitov, E., & Crews, F.T. (2004 September). Sweet liking, novelty seeking, and gender predict alcoholic status. Alcoholism: Clinical & Experimental Research, 28(9):1291-1298.
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