Table 1. Description of subjects.

	HC (SD)	IBS (SD)		F	p value	Female IBS vs. female HC Effect size (es) Cohen's d
N	137	73
Bowel habit
Constipation		23
Diarrhea		21
Alternating/mixed		20
Unspecified		9
Normal	137	0
Age	M = 28.62 (9.06)	M = 30.18 (9.43)		1.37	0.24	0.17
HAD anxiety	M = 3.25 (2.53)	M = 5.69 (3.62)		4.21	0.04*	0.83
HAD depression	M = 1.19 (1.64)	M = 2.51 (2.35)		21.89	<0.001**	0.69
EAL (ETI)
EAL prevalencea	16 (12 %)	16 (22 %)		3.25	0.08
EAL total (sqrt)	M = 1.52 (1.07)	M = 1.89 (1.16)		5.28	0.02*	0.34
EAL general	M = 1.35 (1.38)	M = 1.95 (1.72)		1.17	0.28	0.40
EAL physical	M = 0.97 (1.28)	M = 1.21 (1.40)		1.80	0.18	0.18
EAL emotional	M = 0.70 (1.30)	M = 1.23 (1.68)		12.4	0.001**	0.37
EAL sexual	M = 0.40 (0.98)	M = 0.48 (1.14)		0.96	0.33	0.08
CT left sgACC (mm)b	M = 1.79 (0.39)	M = 1.64 (0.35)		4.75	0.03*	–0.40
CT right sgACC (mm)b	M = 1.69 (0.34)	M = 1.62 (0.40)		0.84	0.36	–0.20
	HC (SD)	IBS (SD)	χ2		p value	Female IBS vs. female HC Effect size (es) Cohen's d
Race
African	21 (15.3 %)	10 (13.7 %)
Asian	51 (37.2 %)	18 (24.7%)	5.17		0.16
Caucasian	59 (43.1 %)	43 (58.9 %)
Missing	6 (4.3 %)	2 (2.7 %)

N number of subjects, M mean, SD standard deviation, es effect size (Cohen's d), IBS irritable bowel syndrome, HC healthy controls, Bowel Habit for IBS subjects based on ROME II/III diagnostic criteria, HAD Hospital Anxiety and Depression Scale, EAL early adverse life events, ETI early traumatic inventory (values square root), CT cortical thickness, sgACC subgenual anterior cingulate cortex, mm adjusted in millimeters

^*p < 0.05,

^**p < 0.01

^aEAL total scores ≥9

^bControlled for age and total grey matter volume (TGMV)