Genetics addiction

Mayer P, Hollt V (2005) Genetic disposition to addictive disorders - current knowledge and future perspectives. Curr Opin Pharmacol 5 4—8... 

For reasons that are not yet fully understood, some people seem to develop addictions to street drugs, cigarettes or alcohol more easily than others. There is some evidence that some of this predisposition may be genetically inherited. For instance, the offspring of alcoholics are more likely to become alcoholics themselves, even when not exposed to the social influence of their alcoholic parents. 

Kreek, M.J., Bart, G., Lilly, C., LaForge, K.S., and Nielsen, D.A., Pharmacogenetic and human molecular genetics of opiate and cocaine addictions and their treatments, Pharmacol. Rev., 57, 1, 2005. 

Feng, Y., Niu, T., Xing, H. et al. A common haplotype of the nicotine acetylcholine receptor a4 subunit gene is associated with vulnerability to nicotine addiction in men. Am. J. Hum. Genet. 75 112, 2004. 

Xu Y, Demarest K, Hitzemann R, Sike-la J. Gene coding variant in Casl between the C57BC/6J and DBA/2J inbred mouse strains Linkage to a QTL for ethanol-induced locomotor activation. Alcohol Clin Exp Res 2001, in press. Foroud T, Li T-K. Genetics of alcoholism. A review of recent studies in human and animal models. Am J Addict 1999 8 261-278. 

Nicotine addiction is very complex and pharmacological evidence alongside structure and function analysis of candidate genes may clarify the mechanisms involved. The challenge will be to translate known genetic variation into therapeutic strategies to reduce the prevalence of smoking in the population. 

Nicotine has a wide range of effects on behavior in humans and individual response to nicotine may predict predisposition to addiction. Some individuals may be genetically more likely to be hypersensitive to nicotine and, therefore, find it aversive others may be more positively reinforced by nicotine and seek to repeat the stimulus. Genetically modified animals are increasingly important tools for elucidating the molecular mechanisms involved in addiction. 

Given that there is strong evidence for a genetic component to tobacco addiction the identification of genes that may be responsible for this link leads to exciting new opportunities to help people to withdraw from nicotine and to prevent relapse. 

Picciotto, M. R. and Corrigall, W. A. Neuronal systems underlying behaviors related to nicotine addiction neural circuits and molecular genetics. /. Neurosci. 22 3338-3341, 2002. 

Addiction A primary chronic neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviors that include one or more of the following 5Cs chronicity, impaired control over drug use, compulsive use, continued use despite harm, and craving. 

Strain differences in responses to nicotine are well documented in rodents, albeit these studies have concentrated on species differences using male animals (e.g., Collins et al. 1988). If there are strong strain differences in response to nicotine suggesting genetic vulnerability to or protection from nicotine addiction, sex is most likely another factor that could impact responses to nicotine as well. 

Overall, genetic vulnerability to or protection from nicotine/tobacco addiction shows significant sex differences, which may underlie the differences observed in addiction patterns between males and females, ranging from initiation of smoking to success in quitting. 

Besson M, David V, Suarez S, Cormier A, Cazala P, Changeux JP, Granon S (2006) Genetic dissociation of two behaviors associated with nicotine addiction beta-2 containing nicotinic receptors are involved in nicotine reinforcement but not in withdrawal syndrome. Psychopharmacology 187 189-199... 

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