TABLE 5.

Results of Mann-Whitney U-tests: Differences between concordant and discordant MZ twin pairs in risk behaviors.

DNAm difference (%)	Alcohol use			Cigarette use			Drug abuse
	C n = 32		DC n = 14	C n = 41		DC n = 5	C n = 42		DC n = 4
	Median		P	Median		p	Median		p
CpG1	3.06	7.61	0.02	4.16	0.75	0.03	4.11	2.19	0.16
CpG2	1.93	1.52	0.86	1.77	0.42	0.21	1.75	1.70	0.84
CpG3	2.01	4.51	0.03	2.99	1.34	0.11	2.66	1.76	0.33
CpG4	1.99	2.48	0.50	2.07	1.82	0.35	2.29	0.22	0.03
CpG5	1.32	2.38	0.15	2.00	1.00	0.17	1.90	1.50	0.46
Mean CpG	1.66	3.12	0.06	2.49	0.68	0.03	2.27	0.61	0.09

Note. C, concordant; DC, disconcordant. n = number of MZ twin pairs. Bolded p-values remained significant after Bonferroni p-adjustment.