Table 2.

Imaging genetic analysis of selected SNPs

Neurotransmitter and other related systems	Candidate loci	Variants	p-value
			Genetic main effect	Gene by addiction interaction	Abusers	Controls
Opioid system	OPRD1	rs2234918	0.513	0.364	0.855	0.259
	OPRK1	rs1051660	0.758	0.241	0.294	0.551
	OPRM1	rs1799971	0.163	0.500	0.647	0.134
5-HT system	HTR1B	rs6296	0.942	0.522	0.597	0.683
		rs130058	0.965	0.781	0.880	0.812
	5-HTT	HTTPLR	0.551	0.672	0.480	0.900
Glutamate system	GAD1	rs3791878	0.544	0.460	0.349	0.930
	GRIN2A	rs1070487	0.740	0.814	0.695	0.960
		rs6497730	0.739	0.805	0.712	0.975
GABA system	GABRA2	rs279858	0.049*	0.012*	0.589	0.001*
	GABRG2	rs211014	0.456	0.811	0.507	0.701
DA system	DRD2	rs1079597	0.213	0.806	0.327	0.445
		rs1800497	0.206	0.592	0.222	0.558
	DRD4	VNTR	0.051	0.671	0.097	0.284
Other variants	COMT	rs4680	0.706	0.367	0.748	0.348
	BDNF	rs6265	0.978	0.354	0.553	0.479
	NGFB	rs2239622	0.745	0.285	0.324	0.633
	CSNK1E	rs135745	0.362	0.725	0.412	0.624
	AVPR1R	rs1587097	0.469	0.432	0.990	0.274
	MAOA	rs1137070	0.637	0.280	0.287	0.664
	ZNF804A	rs7597593	0.440	0.625	0.383	0.865
		rs1344706	0.987	0.857	0.905	0.891
GABRA2 variants extended analysis
	Location	GABRA2 variants	Genetic main effect	Gene by addiction interaction	Abusers	Controls
	Intron 9	rs693547	0.145	0.007*	0.357	0.003*
	Intron 8	rs519270	0.069	0.010*	0.494	0.002*
	Intron 7	rs279871	0.056	0.012*	0.589	0.001*
	Exon 5	rs279858	0.049*	0.012*	0.589	0.001*
GABRA2	Intron 4	rs279843	0.011*	0.022*	0.982	0.000*
	Intron 3	rs279827	0.042*	0.045*	0.885	0.003*
	Intron 3	rs10805145	0.027*	0.021*	0.804	0.001*
	Intron 3	rs9291283	0.105	0.196	0.674	0.038*
	Intron 1	rs11503014	0.159	0.972	0.354	0.296

^*p < 0.05. The interactions were tested in a model which included main effects, with “cigarettes smoked per day” and age as covariates