Table 2.

Main effect, interaction and Pearson correlation terms relating FA in a priori white matter tracts and processing speed composite score to diagnostic group and age.

	Main Effect of Group				Main Effect of Age				Group by Age Interaction				Group-wise correlations with age
													BD	HC
	β	t	p	rsp2	β	t	p	rsp2	β	t	p	rsp2	r (p)
Right UF FA	−0.08	−2.59	0.01*	0.09	−.001	−2.58	0.01*	0.10	0.002	2.83	0.006*	0.12	−.40 (.02*)	.21 (.21)
Left UF FA	0.02	0.63	0.53	0.01	0.000	−0.81	0.42	0.01	0.000	−0.21	0.73	0.001	−.14 (.42)	− 24 (.14)
Right SLF FA	−0.01	−0.52	0.61	0.004	−0.001	−1.78	0.08	0.04	0.000	0.57	0.57	0.005	−.35 (.05*)	−.18 (.28)
Left SLF FA	0.000	0.00	0.99	0.00	−0.00	−1.99	0.05	0.05	0.000	.146	0.88	0.00	−.40 (.02*)	−.30 (.07)
PS	12.44	1.23	0.22	0.02	0.51	3.24	0.00**	0.13	−0.41	−1.96	0.05*	0.05	.41 (.02*)	.21 (.21)

Note:

^*p ≤ .05

^**p ≤ .001;

FA = fractional anisotropy; UF = uncinate fasciculus; SLF = superior longitudinal fasciculus; PS = processing speed; BD = bipolar disorder; HC = healthy controls; β = unstandardized beta coefficient; t = t-statistic; r = Pearson correlation coefficient; r_sp² = semi-partial correlation squared; Degrees of freedom for regression = 3; Degrees of freedom for correlation = 32 (BD group) and 37 (HC group).