Table 1.

Standardized Differences in the Means of Covariates in Male Individuals Exposed and Unexposed to a Dependent Stressful Life Event^a

	Scores
Covariate	Total Sample	Discordant DZ Twins	Discordant MZ Twins	Propensity Score–Matched Sample
Years of education	0.045	0.116	0.046	0.027
Mean parental warmth	0.253	0.314	0.044	0.031
Childhood sexual abuse	0.167	0.038	0.078	0.040
Childhood parental loss	0.194	0.036	0.012	0.021
Neuroticism	0.326	0.332	0.072	0.026
Introversion	0.016	0.214	0.068	0.034
Self-esteem	0.117	0.338	0.040	0.033
Early-onset anxiety disorder	0.211	0.146	0.066	0.044
Conduct disorder	0.250	0.092	0.026	0.015
Traumas	0.259	0.170	0.078	0.028
Social support	0.211	0.242	0.112	0.027
Alcohol abuse/dependence	0.256	0.014	0.066	0.025
Nicotine dependence	0.128	0.016	0.078	0.023
Illicit drug abuse/dependence	0.368	0.224	0.038	0.040
Ever divorced	0.098	0.288	0.000	0.032
History of MD >1 y before the FF3 or MM1 interview	0.356	0.334	0.134	0.027
Marital quality	0.395	0.408	0.324	0.024
Difficulties	0.355	0.136	0.030	0.025
Birth year	0.359	0.000	0.000	0.013

Abbreviations: DZ, dizygotic; FF3, third wave; MD, major depression; MM1, telephone contact; MZ, monozygotic.

^aScores with a value of at least 0.25, which meet the definition of a covariate imbalance (a difference of ≥0.25 SD in the mean of the standardized covariate in the 2 groups) are given in boldface type. The propensity score reflects the mean of 10 iterations.