Table 1.

Demographic data for healthy, unaffected and MDD patient samples

	Healthy individuals	MDD patients
N	111	84
Age, years	33.00 (9.23)	48.82 (8.93)
Sex (male/female)	55/56	27/57
Full-scale IQ	108.00 (8.45)	117.18 (11.34)
BDI	n.a	15.25
Medication	None	59 antidepressants/25 unmedicated
5HTTLPR diallelic
Allele frequency	S = 0.43, L = 0.57	S = 0.48, L = 0.52
Genotype frequency	S/S = 0.16, S/L = 0.53, L/L = 0.31	S/S = 0.31, S/L = 0.345, L/L = 0.345
5HTTLPR triallelic
Allele frequency	n.a	S = 0.49, LG = 0.07, LA = 0.44
Genotype frequency	n.a	S/S = 0.32, S/LG = 0.06
		LG/LG = 0.01, S/LA = 0.29
		LA/LG = 0.05, LA/LA = 0.27
BDNF Val66Met
Allele frequency	Val = 0.79, Met = 0.21	Val = 0.80, Met = 0.20
Genotype frequency	Val/Val = 0.62, Val/Met = 0.34, Met/Met = 0.04	Val/Val = 0.62, Val/Met = 0.34, Met/Met = 0.04
Epistasis
Genotype frequency	L/L, Val/Val = 0.18	LA/LA, Val/Val = 0.18
	L/L, Met = 0.12	LA/LA, Met = 0.09
	S, Val/Val = 0.44	S or LG, Val/Val = 0.44
	S, Met = 0.26	S or LG, Met = 0.29

Age and full-scale IQ are presented in mean (standard deviation) format. n.a = Not applicable.