+. Oprd1, +. Hyb-oprd1, and . Bl6, Diagnostic and Statistical Manual of Mental Disorders, American Psychiatric Association, issue.9 22 8 12, 1994.

C. Nederkoorn, C. Braet, S. Van-eijs, A. Tanghe, and A. Jansen, Why obese children cannot resist food: The role of impulsivity, Eating Behaviors, vol.7, issue.4, pp.315-322, 2006.
DOI : 10.1016/j.eatbeh.2005.11.005

H. Garavan and R. Hester, The Role of Cognitive Control in Cocaine Dependence, Neuropsychology Review, vol.26, issue.2, pp.337-345, 2007.
DOI : 10.1007/s11065-007-9034-x

F. Moeller, D. Dougherty, E. Barratt, V. Oderinde, and C. Mathias, Increased impulsivity in cocaine dependent subjects independent of antisocial personality disorder and aggression, Drug and Alcohol Dependence, vol.68, issue.1, pp.105-111, 2002.
DOI : 10.1016/S0376-8716(02)00106-0

M. Linnoila, M. Virkkunen, T. George, and D. Higley, Impulse control disorders, International Clinical Psychopharmacology, vol.8, pp.53-56, 1993.
DOI : 10.1097/00004850-199309001-00008

M. Kreek, D. Nielsen, E. Butelman, and S. Laforge, Genetic influences on impulsivity, risk taking, stress responsivity and vulnerability to drug abuse and addiction, Nature Neuroscience, vol.129, issue.11, pp.1450-1457, 2005.
DOI : 10.1073/pnas.082235799

T. Pattij and L. Vanderschuren, The neuropharmacology of impulsive behavior, Trends in Pharmacological Sciences in press, 2008.

C. Contet, B. Kieffer, and K. Befort, Mu opioid receptor: a gateway to drug addiction, Current Opinion in Neurobiology, vol.14, issue.3, pp.370-378, 2004.
DOI : 10.1016/j.conb.2004.05.005

S. Ghozland, H. Matthes, F. Simonin, D. Filliol, and B. Kieffer, Motivational effects of cannabinoids are mediated by mu-opioid and kappaopioid receptors, Journal of Neuroscience, vol.22, pp.1146-1154, 2002.

A. Roberts, L. Gold, I. Polis, J. Mcdonald, and D. Filliol, Increased Ethanol Self-Administration in delta-Opioid Receptor Knockout Mice, Alcoholism: Clinical and Experimental Research, vol.22, issue.9, pp.1249-1256, 2001.
DOI : 10.1016/S0014-2999(98)00423-3

D. Filliol, S. Ghozland, J. Chluba, M. Martin, and H. Matthes, Mice deficient for delta-and mu-opioid receptors exhibit opposing alterations of emotional responses, Nature Genetics, vol.22, pp.195-200, 2000.

B. Everitt and T. Robbins, Neural systems of reinforcement for drug addiction: from actions to habits to compulsion, Nature Neuroscience, vol.52, issue.11, pp.1481-1489, 2005.
DOI : 10.1016/j.neuropharm.2004.06.027

T. Robinson and K. Berridge, The neural basis of drug craving: An incentive-sensitization theory of addiction, Brain Research Reviews, vol.18, issue.3, pp.247-291, 1993.
DOI : 10.1016/0165-0173(93)90013-P

B. Bowers and J. Wehner, Ethanol consumption and behavioral impulsivity are increased in protein kinase Cy null mutant mice, Journal of Neuroscience, vol.21, p.180, 2001.

C. Sanchis-segura and R. Spanagel, Behavioural assessment of drug reinforcement and addictive features in rodents: an overview, Addiction Biology, vol.21, issue.1, p.38, 2006.
DOI : 10.1007/s002130000405

B. Critchlow, The powers of John Barleycorn: Beliefs about the effects of alcohol on social behavior., American Psychologist, vol.41, issue.7, pp.751-764, 1986.
DOI : 10.1037/0003-066X.41.7.751

H. Matthes, R. Maldonado, F. Simonin, O. Valverde, and S. Slowe, Loss of morphine-induced analgesia, reward effect and withdrawal symptoms in mice lacking the ??-opioid-receptor gene, Nature, vol.383, issue.6603, pp.819-823, 1996.
DOI : 10.1038/383819a0

F. Papaleo, B. Kieffer, A. Tabarin, and A. Contarino, Decreased motivation to eat in ??-opioid receptor-deficient mice, European Journal of Neuroscience, vol.288, issue.11, pp.3398-3405, 2007.
DOI : 10.1111/j.1460-9568.2007.05595.x
URL : https://hal.archives-ouvertes.fr/hal-00189394

L. Sharpe, N. Pilotte, T. Shippenberg, C. Goodman, and E. London, Autoradiographic evidence that prolonged withdrawal from intermittent cocaine reduces mu-opioid receptor expression in limbic regions of the rat brain, Synapse, vol.2, issue.4, pp.292-297, 2000.
DOI : 10.1002/1098-2396(20000915)37:4<292::AID-SYN6>3.0.CO;2-V

K. Kirby, N. Petry, and W. Bickel, Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls., Journal of Experimental Psychology: General, vol.128, issue.1, pp.78-87, 1999.
DOI : 10.1037/0096-3445.128.1.78

W. Bickel and D. Marsch, Toward a behavioral economic understanding of drug dependence: delay discounting processes, Addiction, vol.96, issue.1, pp.73-86, 2001.
DOI : 10.1046/j.1360-0443.2001.961736.x

A. Verdejo-garcia, J. Perales, and M. Perez-garcia, Cognitive impulsivity in cocaine and heroin polysubstance abusers, Addictive Behaviors, vol.32, issue.5, pp.950-966, 2007.
DOI : 10.1016/j.addbeh.2006.06.032

T. Lee and C. Pau, Impulse control differences between abstinent heroin users and matched controls, Brain Injury, vol.16, issue.10, pp.341-360, 2002.
DOI : 10.1080/02699050210128915

C. Pau, T. Lee, and S. Chan, The impact of heroin on frontal executive functions, Archives of Clinical Neuropsychology, vol.17, issue.7, pp.663-670, 2002.
DOI : 10.1093/arclin/17.7.663

A. Verdejo, I. Toribio, C. Orozco, K. Puente, and M. Perez-gracia, Neuropsychological functioning in methadone maintenance patients versus abstinent heroin abusers, Drug and Alcohol Dependence, vol.78, issue.3, pp.283-288, 2005.
DOI : 10.1016/j.drugalcdep.2004.11.006

J. Mitchell, V. Tavares, H. Fields, D. Esposito, M. Boettiger et al., Endogenous Opioid Blockade and Impulsive Responding in Alcoholics and Healthy Controls, Neuropsychopharmacology, vol.280, issue.2, pp.439-449, 2007.
DOI : 10.1038/sj.npp.1301226

S. Kim, Opioid Antagonists in the Treatment of Impulse-Control Disorders, The Journal of Clinical Psychiatry, vol.59, issue.4, pp.159-164, 1998.
DOI : 10.4088/JCP.v59n0403

A. Roberts, J. Mcdonald, C. Hyser, B. Kieffer, and H. Matthes, Mu-opioid receptor knockout mice do not self-administer alcohol, Journal of Pharmacology and Experimental Therapeutics, vol.293, pp.1002-1008, 2000.

V. Chefer, B. Kieffer, and T. Shippenberg, Basal and morphine-evoked dopaminergic neurotransmission in the nucleus accumbens of MOR- and DOR-knockout mice, European Journal of Neuroscience, vol.57, issue.7, pp.1915-1922, 2003.
DOI : 10.1016/0361-9230(84)90190-4

S. Patel, I. Stolerman, P. Asherson, and F. Sluyter, Attentional performance of C57BL/6 and DBA/2 mice in the 5-choice serial reaction time task, Behavioural Brain Research, vol.170, issue.2, pp.197-203, 2006.
DOI : 10.1016/j.bbr.2006.02.019

A. Isles, T. Humby, E. Walters, and L. Wilkinson, Common Genetic Effects on Variation in Impulsivity and Activity in Mice, Journal of Neuroscience, vol.24, issue.30, pp.6733-6740, 2004.
DOI : 10.1523/JNEUROSCI.1650-04.2004

J. Keller, A. Keller, B. Bowers, and J. Wehner, Performance of ??7 nicotinic receptor null mutants is impaired in appetitive learning measured in a signaled nose poke task, Behavioural Brain Research, vol.162, issue.1, pp.143-152, 2005.
DOI : 10.1016/j.bbr.2005.03.004

S. Ghozland, K. Chu, B. Kieffer, and A. Roberts, Lack of stimulant and anxiolytic-like effects of ethanol and accelerated development of ethanol dependence in mu-opioid receptor knockout mice, Neuropharmacology, vol.49, issue.4, pp.493-501, 2005.
DOI : 10.1016/j.neuropharm.2005.04.006
URL : https://hal.archives-ouvertes.fr/hal-00187545

M. Job, A. Tang, F. Hall, I. Sora, and G. Uhl, Mu (??) Opioid Receptor Regulation of Ethanol-Induced Dopamine Response in the Ventral Striatum: Evidence of Genotype Specific Sexual Dimorphic Epistasis, Biological Psychiatry, vol.62, issue.6, 2007.
DOI : 10.1016/j.biopsych.2006.11.016

K. Kovacs, I. Szakall, O. Brien, D. Wang, R. Vinod et al., Decreased Oral Self-Administration of Alcohol In ??-Opioid Receptor Knock-Out Mice, Alcoholism: Clinical & Experimental Research, vol.9, issue.7, pp.730-738, 2005.
DOI : 10.1016/S0092-8674(03)00844-4
URL : https://hal.archives-ouvertes.fr/hal-00129902

J. Uslaner and T. Robinson, Subthalamic nucleus lesions increase impulsive action and decrease impulsive choice?????????mediation by enhanced incentive motivation?, European Journal of Neuroscience, vol.21, issue.8, pp.2345-2354, 2006.
DOI : 10.1111/j.1460-9568.2006.05117.x

G. Witkowski and P. Szulczyk, Opioid ?? receptor activation inhibits sodium currents in prefrontal cortical neurons via a protein kinase A- and C-dependent mechanism, Brain Research, vol.1094, issue.1, pp.92-1006, 2006.
DOI : 10.1016/j.brainres.2006.03.119

P. Schmidt, C. Schmolke, F. Musshoff, C. Prohaska, and M. Menzen, Numerical density of ?? opioidreceptor expressing neurons in the frontal cortex of drug related fatalities, Forensic Science International, vol.115, issue.3, pp.219-229, 2001.
DOI : 10.1016/S0379-0738(00)00333-9

J. Dalley, T. Fryer, L. Brichard, E. Robinson, and D. Theobald, Nucleus Accumbens D2/3 Receptors Predict Trait Impulsivity and Cocaine Reinforcement, Science, vol.315, issue.5816, pp.1267-1270, 2007.
DOI : 10.1126/science.1137073
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1892797

L. Tien, Y. Park, L. Fan, T. Ma, and H. Loh, Increased dopamine D2 receptor binding and enhanced apomorphine-induced locomotor activity in ??-opioid receptor knockout mice, Brain Research Bulletin, vol.61, issue.1, pp.109-115, 2003.
DOI : 10.1016/S0361-9230(03)00077-7

L. Clark, T. Robbins, K. Ersche, and B. Sahakian, Reflection Impulsivity in Current and Former Substance Users, Biological Psychiatry, vol.60, issue.5, pp.515-522, 2006.
DOI : 10.1016/j.biopsych.2005.11.007