. Author manuscript; available in PMC: 2012 Feb 1.

Published in final edited form as: J Clin Psychopharmacol. 2011 Feb;31(1):22–30. doi: 10.1097/JCP.0b013e31820465fa

Table 2.

Multilevel Regression Results for the Number of Drinking Days by Medication Group, Age of Alcohol Dependence Onset, and Genotype Group

Predictor Variables	b	SE	t	p
Block 1
Sex	1.027	0.470	2.185	0.031
Age	−0.068	0.021	−3.244	0.002
Short Index of Problems Score	0.004	0.024	0.183	0.855
Lifetime Major Depression Diagnosis	0.999	0.429	2.328	0.022
Baseline Drinking Days	2.563	0.724	3.542	0.001
5-HTTLPR Genotype	−0.075	0.413	−0.183	0.856
Medication Group^a	0.098	0.491	0.200	0.842
Age of Onset of Alcohol Dependence (AD Onset)^a	0.544	0.707	0.769	0.443
AD Onset × Medication Group	−1.117	0.838	−1.333	0.185
Block 2^b
Study Week	0.026	0.046	0.564	0.573
Medication Group × Genotype	−8.295	1.481	−5.600	<0.001
AD Onset × Genotype	−5.396	1.458	−3.700	0.001
Study Week × Medication Group	0.199	0.081	2.462	0.015
Study Week × Genotype	0.169	0.073	2.308	0.023
Study Week × AD Onset	0.277	0.111	2.491	0.014
AD Onset × Genotype × Medication Group	8.560	1.960	4.367	<0.001
Study Week × Medication Group × Genotype	−0.265	0.108	−2.463	0.015
Study Week × AD Onset × Medication Group	−0.546	0.140	−3.895	<0.001
Study Week × AD Onset × Genotype	−0.383	0.138	−2.776	0.007
Study Week × AD Onset × Genotype × Medication Group	0.518	0.184	2.822	0.006

Medication Group is a conditional effect for individuals who have late-onset alcohol dependence (AD); Age of Onset of AD is a conditional effect for individuals who are in the sertraline group.

The 2-way and 3-way interactions in block 2 are conditional effects for individuals coded zero on the predictor(s) not involved in the interaction (but included in the 4-way interaction).