Table 2.

Functional genetic variants.

Gene Symbol	Description	Discovery Method	Addiction Cycle	References
NPY	Neuropeptide Y	Candidate Association	Binge-Intoxication	Mottagui-Tabar et al., 2005; Zhou et al 2008; Xu et al., 2013
HTR2B	5-Hydroxytryptamine Receptor 2B	Candidate Association	Binge-Intoxication	Bevilacqua et al., 2010; Tikkanen et al., 2015
OPRM1	Opioid Receptor Mu 1	Candidate Association	Binge-Intoxication	Lovallo et al., 2015; Ray et al., 2012
DRD2	Dopamine Receptor D2	Linkage	Binge-Intoxication	Filbey et al., 2012; Savitz et al., 2013
DRD4	Dopamine Receptor D4	Linkage	Binge-Intoxication	Filbey et al., 2012; Savitz et al., 2013
CRHR1	Corticotropin Releasing Hormone Receptor 1	Candidate Association	Withdrawal-Negative Affect	Chen et al., 2010; Hansson et al., 2006; Hsu et al., 2012; Ray et al., 2013
FKBP5	FK506 Binding Protein 5	Candidate Association	Withdrawal-Negative Affect	Bevilacqua et al., 2012; Huang et al., 2014
OPRK1	Opioid Receptor Kappa 1	Candidate Association	Withdrawal-Negative Affect	Faisal et al., 2014; Xu et al., 2013; Xuei et al., 2006
PDYN	Prodynorphin	Linkage	Withdrawal-Negative Affect	Karpyak et al., 2013; Preuss et al., 2013
COMT	Catechol-O-Methyltransferase	Linkage	Preoccupation-Anticipation	Tiihonen et al., 1999; Voisey et al., 2011; Dickinson and Elvevag, 2009; Ashare et al., 2013; Goldman et al., 2005b
BDNF	Brain Derived Neurotrophic Factor	Candidate Association	Preoccupation-Anticipation	Chen et al., 2015; Benzerouk et al., 2013
CREB1	CAMP Responsive Element Binding Protein 1	Candidate Association	Preoccupation-Anticipation	Chen et al., 2015
KCNJ6	Potassium Voltage-Gated Channel Subfamily J Member 6	GWAS endophenotype	Preoccupation-Anticipation	Kang et al., 2012; Crabbe et al., 2006; Tipps and Buck, 2015; Aryal et al., 2009; Blednov et al., 2001; Goldman et al., 2005b; Kozell et al., 2009; Lewohl et al., 1999