Table 2.

Parameters of sleep–wake activity in the bipolar phenotype group and control group.

	Group: mean (SD)		Statistical difference
	Bipolar phenotype, N = 19	Controls, N = 21	F-test (df = 1,34)	p
Sleep onset time: hh:mm	01:11 (01:31)	01:08 (00:55)	0.000	0.986
Final wake time: hh:mm	08:28 (01:13)	08:53 (00:51)	0.926	0.343
Total sleep period hh:mm	07:19 (00:43)	07:43 (00:43)	1.606	0.214
Total sleep time: hh:mm	06:15 (00:39)	06:38 (00:40)	2.754	0.106
Sleep onset latency: hh:mm	00:05 (00:03)	00:06 (00:04)	0.071	0.792
Sleep efficiency: %	84.0 (4.5)	84.6 (3.5)	1.773	0.192
Fragmentation index	30.6 (9.2)	27.4 (6.4)	7.891	0.008