While there seems little doubt that gambling problems are transmitted from one generation to the next, the underlying mechanisms of this transmission are poorly understood.
Among adults, the few behavioural genetics studies that have been carried out on twins show that close to half of the variance in gambling problems can be explained by the transmission of genetic vulnerability: children of parents with gambling problems end up developing gambling habits and, eventually, problems because they inherit the genes that made their parents vulnerable.
Impulsivity, a known predictor for gambling problems, is under moderate genetic control.
Do these findings also apply to early gambling in preadolescents and the personality traits that predict early gambling, such as impulsivity? To answer this question, we carried out a longitudinal study on 460 sets of twins. Impulsivity measurements were obtained from a task carried out in a laboratory setting when the twins were 7 years old. Early gambling habits were assessed by means of a self-reported questionnaire when the twins were 12 years old. Finally, the parents provided information about their own gambling habits when the children were 8 years old.
Our analysis showed that impulsivity, a known predictor for gambling problems, is under moderate genetic control; the remaining variance is explained by environmental factors specific to the non-shared environment of each twin. The influence of shared environmental factors (e.g. socioeconomic status, parent gambling habits) is virtually nil. On the other hand, early gambling habits are under very little or no genetic control; they are influenced by factors linked to the shared and non-shared environment. Further analysis showed parent gambling to be the most significant shared environmental factor. In preadolescents, it is clear that early gambling is the result of socio-familial rather than genetic transmission.
Daniel Pérusse, Université de Montréal
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Deposit of the research report: September 2010