Table 2.

Effects of different factors on N2 amplitude

Effect	Hypothesis d.f., error d.f.	F/T	P-value	Follow-up tests
Group (FEP, CHR, healthy controls)	2, 111	2.358	0.099
Stimulus (target, standard)	1, 111	14.922	<0.001	target > standard***
Regions (ROI1, ROI2, ROI3, ROI4)	3, 109	40.500	<0.001	ROI1 > ROI3*** = ROI4 > ROI2***
Group × stimulus	2, 111	1.760	0.177
Group effect for target
Group effect for standard
Group × regions	6, 220	3.076	0.007
Group effect at ROI1
Group effect at ROI2
Group effect at ROI3
Group effect at ROI4
Group × regions × stimulus	6, 220	1.393	0.219

FEP, first-episode psychosis; CHR, clinical high risk; ROI, region of interest.

^***P < 0.001.