Perceived parenting behaviour in the childhood of cocaine users: relationship with genotype and personality traits

Low parental care during childhood, a pattern characteristic of an ‘‘affectionless control’’ rearing style was frequently reported in the history of addicted individuals. Parents’ childrearing regimes and children’s genetic predispositions, with their own behavioral characteristics, have been seen to be closely interwoven, probably affecting children’s development and addictive behavior susceptibility. In the present study, parents care perception, aggressive personality traits, and genotype (serotonin transporter promoter gene—5-HTTLPR) have been investigated in cocaine users and healthy control subjects. PBI scores (maternal and paternal care) were lower and BDHI scores (aggressiveness) higher in cocaine users in comparison with controls and significant differences in the perception of either paternal or maternal care were observed between cocaine users and non- users. The short-short (SS) genotype frequency was significantly higher among cocaine users compared with control subjects (P=0.04). Logistic regression proves that persons bearing the SS genotype have a risk of becoming cocaine user almost three times higher than those having the LL genotype. Estimations of the effects of other factors potentially affecting the risk of being cocaine addicted clearly prove the significant impact of aggressiveness: the highest the score, the highest the risk of becoming cocaine user. Moreover, paternal and maternal care perception significantly improve the fit of the model (the log likelihood decreases passing from-105.9 to -89.8, LR test=32.17, P-value=0.000). Each unit increase in the PBI score yields a significant 12% and 10% decrease of the risk of becoming cocaine user, respectively for paternal and maternal care. Interestingly, once controller for the PBI score, the relative risk associated to the SS genotype drops strikingly and becomes no longer statistically significant. On the whole, our preliminary data suggest that the association between 5-HT transporter polymorphism and psycho-stimulant use may be mediated by mother–child relationship and parental attachment perception, both being environmental and genetic factors involved in the proneness to substance use disorders, particularly in aggressive-antisocial individuals.