Table 1.

Sample characteristics for alcohol-dependent and healthy control subjects

	AD group (N=119)			Control group (N=97)
	Mean	SD	%	Mean	SD	%	t or χ 2	df	p
Gender (female)			15.1			16.5	0.001	N=216	0.98
Age in years	45.0	10.7		43.7	10.8		0.9	214	0.38
SES	−0.4	1.9		0.7	2.1		−3.6	170	<0.001
Lifetime alcohol intake in kg (pure alcohol)	1805	1121		285	810		11.1	214	<0.001
Alcohol intake per drink year in kg (pure alcohol)	55.5	25.8		10.0	23.3		13.4	214	<0.001
Age of AD onset in years (DSM-IV)	32.0	12.0						N=111
Duration of AD in years (DSM-IV)	11.7	9.9						N=110
Abstinence before MRI in days	22.8	11.5						N=115
ADS	14.8	6.9		2.0	3.0		17.0	213	<0.001
OCDS-G total score	11.9	8.5		2.8	2.8		10.1	207	<0.001
Smokers			76.5			67.0	1.9	N=216	0.16
FTND (sum score)	3.6	2.8		1.4	2.0		6.4	214	<0.001
WHODAS-II	19.9	6.8		13.5	8.4		8.4	204	<0.001
BIS-15 total score	31.6	6.5		29.1	5.5		2.9	205	0.004
TMT (percentile)	36.1	25.1		44.8	25.1		2.5	209	0.014
DSST	64.3	15.1		73.5	16.6		4.2	211	<0.001
DSB	6.5	1.9		7.4	2.0		3.4	214	0.001
MWT	104.7	9.4		104.5	8.9		−0.2	209	0.82

Socioeconomic status (SES): sum of z-transformed self-ratings of social status, household income and inverse personal debt scores²⁹; Alcohol Dependence Scale (ADS): degree/level of AD³⁰; Obsessive Compulsive Drinking Scale (OCDS-G): current craving for alcohol³¹; Fagerström test for nicotine dependence (FTND): intensity of physical addiction to nicotine; Disability Assessment Schedule 2.0 of the World Health Organization (WHODAS-II): generic assessment instrument for health and disability; Barratt Impulsiveness scale (BIS-15): impulsivity³²; trail making test (TMT): visual attention and task switching; digit symbol substitution test (DSST): processing speed; digit span backwards (DSB): working memory; multiple-choice vocabulary intelligence test (Mehrfachwahl-Wortschatz-Intelligenztest, MWT): crystallized/verbal intelligence