Table 3.

Demographic and clinical predictors of Stage 3 sleep, slow wave sleep and REM sleep.

	Standardized beta coefficients
Predictor	Stage 3 min	Stage 3%	SWS min	SWS %	REM min	REM %
Cocainea	−0.413***	−0.461***	−0.346**	−0.402***	0.488***	0.456***
Alcoholb	−0.366***	−0.401***	−0.315**	−0.352***	0.268**	0.323***
BMI	−0.225**	−0.230**	−0.212**	−0.218**	0.121	0.106
Age	−0.163**	−0.092	−0.234**	−0.168**	−0.175**	−0.048
African American	−0.127	−0.092	−0.152*	−0.125	−0.125	−0.111
Cigarette use	−0.060	−0.033	−0.021	0.008	0.091	0.102
Education	0.036	0.022	0.072	0.061	−0.043	−0.036
HAMD‐24	0.043	0.041	0.084	0.090	−0.146*	−0.201**
Overall R 2	0.343***	0.327***	0.312***	0.294***	0.244***	0.223***

^aCocaine group versus others,

^balcohol group versus others; BMI = body mass index, HAMD‐24 = Hamilton Rating Scale For Depression, 24 items; REM = rapid eye movement, SWS = slow wave sleep;

^* P < 0.10,

^** P < 0.05,

^*** P < 0.001.