Table 4.

Polygenic analyses reveal specific associations between unipolar depression risk and medial prefrontal thickness

	Discovery GWAS		Genotype data		Imputed data
	p value	SNP #	p	R2	p	R2
Major depressive disorder	< 0.1	122,072	0.003	0.020	0.005	0.018
	< 0.2	236,773	0.003	0.020	0.006	0.017
	< 0.3	348,603	0.002	0.021	0.005	0.018
	< 0.4	456,525	0.002	0.021	0.006	0.017
	< 0.5	564,290	0.004	0.018	0.011	0.011
Bipolar disorder	< 0.1	125,854	0.314	0.002	0.313	0.002
	< 0.2	235,719	0.396	0.002	0.318	0.002
	< 0.3	341,228	0.474	0.001	0.416	0.001
	< 0.4	443,095	0.445	0.001	0.412	0.002
	< 0.5	543,664	0.992	0.001	0.701	0.001

The number of risk profile SNPs that satisfy each p value threshold based on the discovery GWAS data is shown. The study datasets consist of allele information for 763,104 genotyped SNPs and dosage data for 5,597,521 imputed SNPs; R², total variance in mPFC thickness accounted for by each polygenic factor after partialing out variance associated with collection site, scanner software, estimated IQ, multidimensional scaling components of genetic ancestry, number of nonmissing SNPs, age, and sex.