Table 1.

Comparison between bipolar disorder patients, unaffected siblings and healthy controls in terms of demographic and clinical characteristics

	Bipolar disorder patientsa (N = 60)		Unaffected siblingsb (N = 49)		Healthy controlsc (N = 71)		Significance
	N	%	N	%	N	%	df	F or χ2	p value	Group comparison
Female	40	66.7	34	69.4	37	52.1	2	4.621	0.10	a = b = c
Caucasian	34	56.7	26	53.1	26	36.6	2	6.00	0.050	a = b = c
Bipolar disorder type I with psychotic features	52	86.7	–	–	–	–	–	–	–
	47	90.4	–	–	–	–	–	–	–
Bipolar disorder type II with psychotic features	8	13.3	–	–	–	–	–	–	–
	1	12.5	–	–	–	–	–	–	–
	Mean	S.D.	Mean	S.D.	Mean	S.D.
Age (in years)	38.0	10.6	38.9	10.3	37.8	11.8	2179	0.18	0.839	a = b = c
										a=c
Premorbid IQ (WRAT-3)	97.7	10.7	97.2	10.6	98.3	10.0	2167	0.15	0.864	a = b = c
Depressive symptoms (HRSD)	6.8	5.8	2.9	2.6	2.0	2.7	2179	24.65	<0.001	a > b = c*
										a> c*
Manic symptoms (CARS-M)	3.8	4.7	1.3	1.4	0.9	1.3	2179	17.95	<0.001	a > b = c*
										a> c*

WRAT-3, Wide Range Achievement Test–third edition; CARS-M, Clinician Administered Rating Scale for Mania.

^*The mean difference is significant at the 0.05 level using Least Significance Difference correction for multiple comparison