Table 1.

Bidirectional causal associations between disorders and between lower intelligence and risks for SCZ, BD, SCZ + BD, or SCZ versus BD.

Phenotypes		GSMR results
Exposure (bzx)	Outcome (bzy)	bxy	SE	OR	p value	index SNPs (N)
SCZ	BD	0.387	0.029	1.47	2.89 × 10−41	55
BD	SCZ	0.362	0.024	1.44	1.85 × 10−52	57
lower intelligence	SCZ	0.482	0.063	1.62	3.23 × 10−14	116
SCZ	lower intelligence	0.056	0.006	1.06	3.70 × 10−23	48
lower intelligence	BD	0.083	0.075	1.09	0.27	125
BD	lower intelligence	−0.009	0.005	0.99	0.06	52
lower intelligence	SCZ + BD	0.207	0.050	1.23	3.41 × 10−5	113
SCZ + BD	lower intelligence	0.042	0.006	1.04	3.09 × 10−14	75
lower intelligence	SCZ vs. BD	0.493	0.081	1.64	9.72 × 10−10	129
SCZ vs. BD	lower intelligence	−0.001	0.008	1.00	0.88	19

Abbreviations: BD, bipolar disorder; GSMR, generalized summary-data-based Mendelian randomization; SCZ, schizophrenia; SE, standard error; OR, odds ratio. P values are shown in boldface if p < 0.05.