You are seeing this message because your Web browser does not support basic Web standards. Find out more about why this message is appearing and what you can do to make your experience on this site better.


ABOUT ARCHIVES
Advanced Search

Welcome   | My Account | E-mail Alerts | Access Rights | Sign In


  Vol. 59 No. 12, December 2002 TABLE OF CONTENTS
  Archives
  •  Online Features
  Original Article
 This Article
 •Abstract
 •PDF
 • Reply to article
 •Send to a friend
 • Save in My Folder
 •Save to citation manager
 •Permissions
 Citing Articles
 •Citation map
 •Citing articles on HighWire
 •Citing articles on Web of Science (62)
 •Contact me when this article is cited
 Related Content
 •Similar articles in this journal
 Topic Collections
 •Men's Health
 •Men's Health, Other
 •Antisocial Personality Disorder
 •Depression
 •Public Health
 •Substance Abuse/ Alcoholism
 •Genetics
 •Genetic Disorders
 •Alert me on articles by topic
 Social Bookmarking
  Add to CiteULike Add to Connotea Add to Del.icio.us Add to Digg Add to Reddit Add to Technorati Add to Twitter What's this?

Shared Genetic Risk of Major Depression, Alcohol Dependence, and Marijuana Dependence

Contribution of Antisocial Personality Disorder in Men

Qiang Fu, MD,PhD; Andrew C. Heath, DPhil; Kathleen K. Bucholz, PhD; Elliot Nelson, MD; Jack Goldberg, PhD; Michael J. Lyons, PhD; William R. True, PhD,MPH; Theodore Jacob, PhD; Ming T. Tsuang, MD,PhD,DSc; Seth A. Eisen, MD,MSc

Arch Gen Psychiatry. 2002;59:1125-1132.

ABSTRACT

Background  Little is known about genetic factors that underlie the interrelationships among antisocial personality disorder (ASPD), major depression (MD), alcohol dependence (AD), and marijuana dependence (MJD). We examined the contribution of genetic effects associated with ASPD to the comorbidity of MD and substance use disorders.

Methods  The Vietnam Era Twin Registry is a general population registry of male veteran twins constructed from computerized Department of Defense files and other sources. A telephone diagnostic interview was administered to eligible twins from the Registry in 1992. Of 5150 twin pairs who served on active military duty during the Vietnam era, 3360 pairs (1868 monozygotic and 1492 dizygotic) in which both members completed the pertinent diagnostic interview sections were included. The main outcome measures were lifetime DSM-III-R ASPD, MD, AD, and MJD.

Results  Structural equation modeling was performed to estimate additive genetic, shared environmental, and nonshared environmental effects common and specific to each disorder. The heritability estimates for lifetime ASPD, MD, AD, and MJD were 69%, 40%, 56%, and 50%, respectively. Genetic effects on ASPD accounted for 38%, 50%, and 58% of the total genetic variance in risk for MD, AD, and MJD, respectively. After controlling for genetic effects on ASPD, the partial genetic correlations of MD with AD and with MJD were no longer statistically significant. Genetic effects specific to MD and AD and familial effects specific to MJD remained statistically significant. Nonshared environmental contributions to the comorbidity in these disorders were small.

Conclusions  In this sample, the shared genetic risk between MD and both AD and MJD was largely explained by genetic effects on ASPD, which in turn was associated with increased risk of each of the other disorders.



INTRODUCTION
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

THE ROLE of antisocial personality disorder (ASPD) as a confounding factor in genetic research on the comorbidity of major depression (MD) and substance use disorders has received insufficient attention. It has been found that substance use disorders co-occur with MD and with ASPD, possibly indicating common risk factors shared by these conditions. However, understanding of the interrelationships among these disorders has been limited by a failure to consider the comorbidity between MD and ASPD, which is a major risk factor for substance use disorders.

Major depression and alcohol dependence (AD) have been found to co-occur at higher than expected rates in clinical1-3 and epidemiologic samples.4-10 Antisocial personality disorder exhibits a similar strong association with AD.3, 6, 11-19 Psychiatric comorbidity with marijuana dependence (MJD) has received less attention. Men and women with lifetime DSM-IV MD in US national surveys had a significant increase in risk of MJD.20-21 Although antisocial behaviors have been found to be associated with marijuana use,22-25 data on comorbidity between adult ASPD and MJD are scant. The results of a few studies7, 21 suggest that most respondents with ASPD report a history of drug dependence.

Substantial genetic effects have been reported for risk of MD,26-31 childhood conduct disorder,32-36 adult ASPD,32, 36-38 AD,39-47 and MJD.48-52 The hypotheses that common genetic susceptibilities underlie the comorbidity among substance use disorders, MD, and ASPD (or its precursor, conduct disorder) have found some support in genetic epidemiologic studies. Comorbidity of MD and AD has been found to be familial in some studies,40, 53-58 but not in others.59-61 Several twin and adoption studies,40, 62-64 but not all,65-66 have observed significant genetic correlations between MD and AD. The extent to which genetic vs shared environmental factors contribute to the comorbidity of conduct disorder (or ASPD) and AD has been more controversial. Common genetic risk factors have been suggested to account for 76% and 71% of the phenotypic association between conduct disorder and AD in Australian male and female twins, respectively.34 Shared environmental risk factors were found to be responsible for comorbid conduct disorder and alcohol use disorder in the Vietnam Era Twin (VET) Registry.52 A study32 of monozygotic (MZ) twins reared apart reported a high genetic correlation (r = 0.75) between DSM-III ASPD and AD symptom counts, whereas another study67 of twins reared together found a common genetic vulnerability between DSM-III ASPD and AD in men but an overlap between shared environmental risk factors for ASPD and AD in women.

Family and twin studies have also been used to examine the co-transmission of ASPD and marijuana use disorder. In a recent family study68 of substance use disorder, no familial coaggregation of ASPD and cannabis use disorder was found, but the sample size was relatively small. Data from male twins from the VET Registry suggested52 that shared environmental effects accounted for the comorbidity between conduct disorder and MJD. Empirical studies on genetic contributions to the comorbidity between MD and MJD are lacking.

Interpretation of the comorbidity and apparent shared genetic risk of MD and AD is complicated by the fact that conduct disorder21, 35, 69 and ASPD70-73 have also been found to be associated with increased risk of MD. The comorbidity between ASPD and MD could itself be due to common genetic risk factors, which may be an important confounding factor in studies40, 64 of shared genetic risk between MD and AD. However, the genetic and environmental contributions to the interrelationships among ASPD, MD, AD, and MJD have not yet been explored, to our knowledge. Given that the onset of ASPD (or at least of conduct disorder) often precedes the development of substance dependence,74 it is natural to question whether the genetic correlations between MD and substance use disorders are secondary to the association between ASPD and those disorders.

We report the results of multivariate analyses of structured diagnostic interview data from twins from the VET Registry36 that directly test the hypothesis that shared genetic risk among ASPD, AD, and MJD is a major determinant of the shared genetic risk between MD and AD and between MD and MJD.


METHODS
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

SAMPLE

The VET Registry is a general population registry of male twins constructed in the middle 1980s from computerized Department of Defense files and other sources. Twins born between 1939 and 1957 who served on active military duty during the Vietnam era (1965-1975) were included. Zygosity was assessed using a series of questions about sibling similarity supplemented with limited blood group data obtained from military records. Zygosity determination using such methods has been shown to have 95% accuracy.75 The development and characteristics of the Registry have been published elsewhere.76-77 Registry members participating in research studies have been found to be representative of twins who served in the military during the Vietnam era on a variety of sociodemographic and other variables.77-78

The data reported herein are from structured diagnostic telephone interviews administered to the VET panel in 1992.36, 49 Of 10 300 eligible individuals, 79.7% completed the interview. The overall pairwise response rate was 66.0% (3372 complete pairs). A total of 3360 pairs (1868 MZ and 1492 dizygotic [DZ]) in which both members completed the pertinent diagnostic interview sections are included in the present study. The mean ± SD age at interview of respondents was 42.0 ± 2.7 years (range, 33.0-52.0 years); 93.8% were non-Hispanic white, 5.8% were African American, less than 1% were Hispanic, and 0.3% were of other ethnicity; 33.3% were high school graduates and 38.7% were college graduates; and 92.6% were employed full-time, 1.8% were employed part-time, and 5.6% were unemployed. Further details of the sociodemographic characteristics of the VET panel can be found elsewhere.36, 44, 49

ASSESSMENT OF PSYCHIATRIC DISORDERS

A computerized telephone version of the Diagnostic Interview Schedule, Version 3, Revised,79 was used to assess drug use and abuse or dependence and other axis I psychiatric disorders in all respondents. Experienced interviewers from the Institute for Survey Research at Temple University were trained by one of the project investigators (M.J.L.) to administer the telephone interview. The interview was administered after the respondent had given verbal consent. Lifetime diagnoses of ASPD, MD, AD, and MJD were determined according to DSM-III-R criteria.80 All diagnostic variables were coded dichotomously. Earlier analyses44, 81 of VET Registry data reported good test-retest reliability of diagnostic measures. Because of the high prevalence in this male veteran sample of DSM-III-R AD as assessed by the Diagnostic Interview Schedule, Version 3, Revised, some analyses were repeated using a diagnosis of severe AD according to the DSM-III-R, operationalized following the Diagnostic Interview Schedule, Version 3, Revised, as the reporting of at least 7 symptoms with evidence of interference in occupational functioning or usual social activities or relationships with others.

STATISTICAL ANALYSES

Univariate and multivariate logistic regression analyses were performed to analyze the associations of AD and MJD with ASPD and with MD using statistical software (Stata, release 6.0; Stata Corp, College Station, Tex). Odds ratios and 95% confidence intervals (CIs) were estimated using the Huber-White robust variance estimator (Stata) to correct for the correlation between 2 members of each twin pair (which would otherwise lead to underestimation of 95% CIs for the odds ratios).

Genetic analyses of twin pair data used a normal liability threshold model82 to decompose the total phenotypic variance in risk of each disorder ("liability") into genetic, shared environmental, and nonshared environmental components. Use of a threshold model implies the assumption, plausible for the specific disorders considered herein, that for each disorder there is a continuous and approximately normal distribution of risk in the general population, which is determined by the combined effects of multiple genetic and environmental risk factors. In univariate analyses, tetrachoric correlations (ie, correlations for liability to a disorder) are estimated separately for MZ and DZ pairs using standard maximum-likelihood methods.83-84 Under the assumption that MZ and DZ pairs do not differ in their concordance for pertinent shared environmental risk factors (eg, parental psychiatric disorders and neighborhood risk factors), because MZ pairs are genetically identical and DZ pairs are genetically no more alike than ordinary full siblings, comparing MZ and DZ twin correlations provides a test for genetic effects.27 These twin pair tetrachoric correlations are used to estimate the contribution of genes and environmental (shared and nonshared) effects to variation in risk of a disorder. In this VET panel, there was little evidence for higher environmental correlations for MZ vs DZ twin pairs.85 The heritability of a disorder is defined as the proportion of the total variance in risk accounted for by genetic effects. In previous publications, univariate twin analyses of the VET sample showed significant additive genetic and nonshared environmental, but not shared environmental, effects on MD,30 ASPD,36 and AD44 and significant genetic and shared and nonshared environmental effects on MJD.49-50,52

In the present study, our primary interest was in the interrelationships among the 4 disorders, so we extended the univariate analysis approach to the multivariate case. In multivariate analyses, 3 kinds of tetrachoric correlations (cross-twin within-variable, within-twin cross-variable, and cross-twin cross-variable correlations) were used to estimate the relative contributions of genetic, shared environmental, and nonshared environmental effects to the comorbidity of the 4 disorders.86 Results are summarized by genetic, shared environmental, and nonshared environmental correlations: for example, a genetic correlation of unity implies complete overlap of genetic risk factors for 2 disorders, whereas a genetic correlation of zero will occur if there is complete independence of genetic risk factors for the disorders. Similar interpretations may be given to the environmental sources of variation.

Matrices of tetrachoric correlations between the 4 disorders assessed in each twin (ie, 8 x 8 matrices) were estimated separately for MZ and DZ pairs using PRELIS 2.83 Multivariate genetic models were fitted by asymptotic weighted least squares using a structural equation modeling program (Mx; Virginia Commonwealth University, Richmond).86 We began by fitting a full Cholesky ("triangular decomposition") model (Figure 1). For each source of variation (ie, genetic effects, shared environmental effects, and nonshared environmental effects), this model estimates as many latent factors as there are observed variables (ie, diagnoses), but with a triangular pattern of factor loadings. Thus, all observed variables are allowed to have nonzero loadings on the first factor; the second observed variable and all subsequent observed variables are allowed to have nonzero loadings on the second factor; the third and fourth observed variables (in our application) are allowed to have nonzero loadings on the third factor; and, finally, only the fourth observed variable is affected by the fourth factor. From this full model, predicted genetic and environmental variances in risk of each disorder, and genetic and environmental correlations between disorders, may be derived.86



View larger version (49K):
[in this window]
[in a new window]
Figure 1. Path diagram of the genetic and environmental interrelationships among antisocial personality disorder (ASPD), major depression (MD), alcohol dependence (AD), and marijuana dependence (MJD) for an individual twin under a Cholesky triangular decomposition model. The variance in liability for each disorder is partitioned into additive genetic (A), shared environmental (C), and nonshared environmental (E) effects. One-way arrows represent factor loadings used to compute variances. A, The additive genetic variance for MJD is further partitioned into that shared with ASPD, MD, and AD and MJD-specific effects; the additive genetic variance for AD is partitioned into that shared with ASPD and MD and AD-specific effects; the additive genetic variance for MD is partitioned into that shared with ASPD and MD-specific effects. B, The shared environmental variance for each disorder is similarly decomposed. C, The nonshared environmental variance for each disorder is similarly decomposed. All additive genetic, shared environmental, and nonshared environmental factor loadings were estimated simultaneously.


Under the full model, the ordering of observed variables is arbitrary, but this is not the case for submodels, in which 1 or more genetic or environmental factor loadings are fixed to zero. To test the hypothesis that the genetic correlations between MD and both AD and MJD could be entirely explained by genetic effects associated with ASPD, we fitted a submodel (model 4 in Figure 2) that estimated the first genetic factor with nonzero loadings of ASPD, MD, AD, and MJD; the second genetic factor with a nonzero loading of MD only (ie, fixing to zero the genetic paths to AD and MJD, thereby implying zero partial genetic correlations between MD and AD and between MD and MJD when genetic effects associated with ASPD were controlled for); and the third and fourth genetic factors with the nonzero loadings shown in Figure 1. We compared this model with a model that reordered the diagnostic variables as MD, ASPD, AD, and MJD, with the first genetic factor having nonzero loadings on all variables but the second genetic factor having a nonzero loading on ASPD only (ie, fixing to zero the genetic paths to AD and MJD, thereby implying zero partial correlations between ASPD and both AD and MJD once genetic effects on risk of MD were controlled for), with third and fourth genetic factors again having the same nonzero loadings shown in Figure 1. Finally, under model 3 (Figure 2), we estimated likelihood-based 95% CIs84 for the proportion of the total genetic correlations between MD and AD and between MD and MJD that could be accounted for by the ASPD genetic factor.



View larger version (91K):
[in this window]
[in a new window]
Figure 2. Path diagrams for the models compared in Table 2. Risk of antisocial personality disorder (ASPD), major depression (MD), alcohol dependence (AD), and marijuana dependence (MJD) (shown for an individual twin) is partitioned into additive genetic (A) and shared environmental (C) effects. In each model, factor loadings for nonshared environmental effects (E in Figure 1) (ie, no loadings were fixed to zero) are not shown. One-way arrows represent effects that were included in the model. Note that under model 4, there are no residual genetic correlations between MD and AD and between MD and MJD after controlling for the ASPD genetic factor (ie, the paths from AMD to AD and to MJD are omitted). Under model 4a, there are no residual genetic correlations between ASPD and AD and MJD after controlling for the MD genetic factor (ie, the paths from AASPD to AD and to MJD are omitted).



View this table:
[in this window]
[in a new window]
Table 2. Goodness-of-Fit Results From Models for Comorbidity of Lifetime Antisocial Personality Disorder (ASPD), Major Depression (MD), Alcohol Dependence (AD), and Marijuana Dependence (MJD)*


The overall fit of each model tested was assessed using goodness-of-fit {chi}2 (with P<.05 indicating a poor fit to the data) and the Akaike Information Criterion, with the lowest Akaike Information Criterion value indicating the most parsimonious model.87-88 The fit of nested models, in which the second model is a submodel of the first, with 1 or more factor loadings fixed to zero, was compared using the likelihood ratio test, with a statistically significant {chi}2 value (P<.05) indicating that the second model gave a statistically significantly worse fit than the first.


RESULTS
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

Lifetime prevalence of DSM-III-R ASPD, MD, AD, and MJD in the VET Registry sample was 2.7%, 9.2%, 35.2%, and 6.6%, respectively. Lifetime prevalence of DSM-III-R severe AD was 6.9%. Thirty-six percent of respondents with ASPD met lifetime criteria for MD compared with 8% of those without a history of ASPD. Table 1 summarizes associations among lifetime DSM-III-R diagnoses of ASPD, MD, AD, and MJD. A history of either ASPD or MD was associated with increased risk for lifetime AD, severe AD, or MJD compared with those without these disorders. Adjusted odds ratios for lifetime AD or MJD when both ASPD and MD were included as predictors were only modestly reduced compared with unadjusted odds ratios.


View this table:
[in this window]
[in a new window]
Table 1. Risks for Lifetime DSM-III-R Alcohol Dependence (AD), Severe AD, or Marijuana Dependence (MJD) Associated With Antisocial Personality Disorder (ASPD) and Major Depression (MD)*


Model fit indices are summarized in Table 2. A companion path diagram (Figure 2) illustrates graphically the assumptions about genetic and shared environmental factors of the models compared. In multivariate twin analyses, 4 genetic, 4 shared environmental, and 4 nonshared environmental factors were estimated under the full model (model 1 in Figure 2). This model gave a good fit to the data (P = .18). Model 2, which tested the hypothesis of no genetic effect on any of the disorders by constraining to zero the paths from the 4 genetic factors to the 4 disorders, gave a very poor fit (P<.001). Model 3, which tested the hypothesis that there was no shared environmental effect on any disorder by fixing to zero all the shared environmental paths, gave a very good fit (P = .39). The fit of this model was not statistically significantly worse than that of the full model using the likelihood ratio test ({chi}210 = 5.3; P = .87).

Under model 3, the paths from the genetic factor for MD (AMD) to AD and to MJD were not statistically significant; therefore, we fixed them to zero to test the hypothesis that the genetic correlations between MD and both AD and MJD could be entirely accounted for by genetic effects associated with ASPD. This submodel (model 4) gave an excellent fit to the data (P = .33), and the fit of this model was not statistically significantly worse than that of model 3 ({chi}22 = 3.5; P = .17). Model 4a tested the alternate hypothesis that the genetic correlations between ASPD and both AD and MJD could be entirely accounted for by genetic effects on MD, that is, the hypothesis that there were no significant residual genetic correlations between ASPD and both AD and MJD after controlling for genetic effect on MD. This submodel produced a poor fit to the data (P = .02) and a substantially worse fit than model 3 by AIC. These results were consistent with the hypothesis that genetic effects on ASPD are a major determinant of the genetic correlation between MD and both AD and MJD (models 3 and 4), but they did not support the alternate hypothesis that genetic effects on MD could account for the genetic correlation between ASPD and both AD and MJD.

Because previous studies49-50,52 from this twin panel suggested shared environmental effects on MJD, we also fitted a model that allowed for genetic and shared environmental effects specific to MJD (model 5). This model gave a fit as good as model 4, with neither genetic nor shared environmental effects specific to MJD being statistically significant, indicating that it was not possible to distinguish whether the remaining familial effects specific to MJD were genetic or shared environmental in origin. We therefore reported parameter estimates of genetic and shared environmental effects for the final model (model 5).

Under model 5 (see Figure 3 for genetic and environmental factor loadings), the heritabilities of lifetime DSM-III-R ASPD, MD, AD, and MJD were 69%, 40%, 56%, and 50%, respectively. Genetic effects on ASPD accounted for 15% of the total phenotypic variance for MD, 28% for AD, and 29% for MJD. Furthermore, of the total genetic variances in risk for MD and AD, 38% (0.392/[0.502 + 0.392]) and 50% (0.532/[0.532 + 0.532]) were explained by the ASPD genetic factor. Approximately 58% (0.542/[0.542 + 0.082 + 0.452]) of the genetic and 46% (0.542/[0.542 + 0.082 + 0.452 + 0.362]) of the total familial (genetic and shared environmental) variance in risk of MJD was also accounted for by the ASPD genetic factor. After controlling for the ASPD genetic factor, the partial genetic correlations between MD and AD and between MD and MJD remained statistically significant. After controlling for ASPD and other genetic risk factors, the 95% CIs of genetic and shared environmental factor loadings specific to MJD were broad (95% CI, 0-0.65 and 0-0.58, respectively), suggesting that important genetic and shared environmental effects specific to MJD could not be excluded. We found statistically significant nonshared environmental effects on risk for each disorder. However, the contributions of nonshared environmental effects to the total phenotypic covariance among these 4 disorders were found to be small, indicating that nonshared environmental effects were less important in understanding the comorbidity among these 4 disorders.



View larger version (41K):
[in this window]
[in a new window]
Figure 3. Factor loadings (95% confidence intervals) from the final model (model 5 in Figure 2). Phenotypic variance has been standardized to unity for each variable. Heritability is estimated as the sum of the squared factor loadings for each diagnosis: antisocial personality disorder (ASPD), 0.832 = 69%; major depression (MD), 0.392 + 0.502 = 40%; alcohol dependence (AD), 0.532 + 0.532 = 56%; and marijuana dependence (MJD), 0.542 + 0.082 + 0.452 = 50%. A indicates additive genetic effects; C, shared environmental effects; and E, nonshared environmental effects.


These analyses show that genetic effects associated with ASPD made a significant contribution to the genetic correlations between MD and AD and between MD and MJD. The residual genetic correlations between MD and AD and between MD and MJD were not statistically significant. Under model 3, we decomposed the total genetic correlations between MD and AD and between MD and MJD into 2 parts associated with MD and ASPD genetic factors, respectively. We found that 21.6% (95% CI, 0%-51.4%) of the total genetic correlation between MD and AD and 38.4% (95% CI, 0%-64.5%) between MD and MJD could be explained by the MD genetic factor and the remainder (78.4%; 95% CI, 49.6%-100%, and 61.6%; 95% CI, 35.5%-100%, respectively) by the ASPD genetic factor. This supports the original hypothesis that the genetic effects associated with ASPD largely account for the genetic correlations between MD and AD and between MD and MJD.


COMMENT
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

In this US military veteran male twin sample, the interrelationships among DSM-III-R ASPD, MD, AD, and MJD almost entirely reflected common genetic (rather than common environmental) effects. Substantial proportions of the genetic variance in risk of AD and of the total familial (genetic and shared environmental) variance in risk of MJD were accounted for by genetic effects associated with ASPD. A history of ASPD predicted a 4-fold increase in the probability of reporting a history of MD, and 38% of the total genetic variance in risk of MD was associated with ASPD. Genetic effects associated with ASPD were a major determinant of the common genetic risk between MD and AD and between MD and MJD. Other researchers40, 64 have reported a substantial genetic correlation between MD and AD. We believe that the present study represents the first attempt to parcel out effects attributable to ASPD from the overall genetic correlation between these 2 disorders. In these male twins, 78% of the genetic correlation between MD and AD and 62% of the genetic correlation between MD and MJD was explained by the genetic factor associated with ASPD, with these percentages not differing significantly from 100%.

Although the assessment of psychiatric disorders in the present study was based on lifetime diagnostic criteria, the model-fitting results suggest that, at least in men, the genetic correlations between MD and substance use disorders are largely secondary to the association between the genetic risk associated with ASPD and these disorders. This conclusion is supported by the fact that the alternative model (model 4a in Figure 2, reversing the order of ASPD and MD) did not fit the data well. In addition, the ordering of the psychiatric disorders in our model is supported by the temporal ordering reported by clinical and epidemiologic studies,6, 21, 74, 89 although temporal ordering need not imply direction of causal effects.

Whether there are sex differences in determinants of the common genetic vulnerability between MD and AD needs to be addressed in future research in samples of female twins. It is possible that analyses of other data will determine that the contribution of ASPD to the genetic correlation between MD and AD is much less important in women than in men; such a sex difference could explain reports of a sex-specific genetic correlation between MD and AD.64 Consistent with this interpretation is the finding that ASPD and AD were genetically correlated in men but environmentally correlated in women67 and that genetic effects on MD in men and women were not perfectly correlated.29

It is plausible that an important role of ASPD in accounting for shared genetic risk between MD and both AD and MJD will also be found for dependence on other classes of drugs. This possibility is suggested by family studies90-92 showing strong familial effects on the co-occurrence of different categories of drugs and by twin studies50 explicitly demonstrating genetic effect common to different classes of drug abuse or dependence.

The results of this study should be interpreted with several caveats. Our sample was composed of a relatively homogenous group of middle-aged and predominantly white male US military veterans, precluding generalization to women and other ethnic groups. Previous examinations30, 44, 49-50,93 of this twin panel (perhaps because of the ready availability of alcohol and drinking companions during military services) have observed a higher prevalence of AD and comparable figures for MD and MJD than was obtained from nonveteran men. The implications of these differences may limit the generalizability of our results to the general population, as discussed in detail in previous studies.30, 44, 49-50 It does not, however, seem that the broad AD phenotype identified by the Diagnostic Interview Schedule, Version 3, Revised, explains our results. When severe AD was predicted jointly from ASPD and MD, the association with ASPD was no less strong. Entry into military service probably excluded individuals with the most severe, early-onset antisocial behaviors. The much lower prevalence of DSM-III-R ASPD in this twin sample (2.7%) compared with that in men in the US general population (5.8%) supports this statement.4 This sample selection bias may have led to the disproportionate inclusion of individuals with ASPD who have mild to moderate antisocial behaviors but would be expected to attenuate rather than exaggerate associations between ASPD and AD. Heritability estimates of MD, AD, and MJD in this twin panel are similar to results from other nonveteran samples.29, 34, 94 Thus, it seems implausible that our findings are based on an artefactual contribution of ASPD to the genetic correlations of MD with AD and with MJD.

An additional limitation is that the models fitted are latent variable models, which do not attempt to specify causal relationships between variables at the phenotypic level.95 Thus, we cannot distinguish between the possibility that ASPD is itself a major mediator of genetic effects on risk of MD and risks for AD and MJD vs the possibility that there are genetic effects on impulsive traits that are associated with increased risk of ASPD, MD, and substance use disorders.

The results of the present study confirm that, at least in men, genetic effects on risk of ASPD are a major determinant of risk of substance dependence. Because of the strong comorbidity between ASPD and MD, failure to control for ASPD may have led to an overstatement of the importance of MD in the inheritance of AD and MJD.64


AUTHOR INFORMATION
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

Submitted for publication September 10, 2001; final revision received April 16, 2002; accepted April 22, 2002.

The authors are grateful for support by grants DA04604, DA07261, AA07788, AA11998, DA14363, DA14632, AA12640, AA11667, and AA11822 from the National Institutes of Health, Bethesda, Md.

The US Department of Veterans Affairs has provided financial support for the development and maintenance of the Vietnam Era Twin (VET) Registry. Numerous organizations have provided invaluable assistance in the conduct of this study, including the following: Department of Defense, Arlington, Va; National Personnel Records Center, National Archives and Records Administration, Washington, DC; the Internal Revenue Service; National Opinion Research Center, Chicago, Ill; National Research Council, National Academy of Sciences, Washington, DC; and the Institute for Survey Research, Temple University, Philadelphia, Pa. Most important, we gratefully acknowledge the continued cooperation and participation of the members of the VET Registry and their families. Without their contribution, this research would not have been possible.

Presented in part at the Eighth World Congress on Psychiatric Genetics, Versailles, France, August 28, 2000.

We acknowledge the work of the following people: (1) Seattle Epidemiologic Research and Information Center Vietnam Era Twin Registry: Edward J. Boyko, MD (director); Jack Goldberg, PhD (epidemiologist); K. Bukowski (registry programmer); Mary Ellen Vitek (coordinator); and Rita Havlicek (statistical assistant); (2) Vietnam Era Twin Registry Advisory Committee: E. Coccaro, MD, PhD; Theodore Colton, ScD; Walter E. Nance, MD, PhD; Ralph S. Paffenbarger, Jr, MD, DrPH; Myrna M. Weissman, PhD; and Roger R. Williams, MD (past); and (3) Veterans Affairs Headquarters: John R. Feussner, MD (chief research and development officer); John Demakis, MD (Health Services Research and Development Service director); and Shirley Meehan, MBA, PhD (deputy director).

Corresponding author and reprints: Qiang Fu, MD, PhD, Missouri Alcoholism Research Center at Washington University, Department of Psychiatry, Washington University School of Medicine, 40 N Kingshighway Blvd, Suite 2, St Louis, MO 63108 (e-mail: qfu{at}matlock.wustl.edu).

From the Missouri Alcoholism Research Center at Washington University, Departments of Psychiatry (Drs Fu, Heath, Bucholz, and Nelson) and Internal Medicine (Dr Eisen), Washington University School of Medicine, St Louis, Mo; the Department of Veterans Affairs, Vietnam Era Twin Registry/Seattle Epidemiologic Research and Information Center, Seattle, Wash (Dr Goldberg); the Department of Epidemiology, University of Washington School of Public Health, Seattle (Dr Goldberg); the Department of Psychology, Boston University, Boston, Mass (Dr Lyons); the Institute of Psychiatric Epidemiology and Genetics, Harvard Medical School, Boston (Drs Lyons and Tsuang); Saint Louis University School of Public Health, St Louis (Drs Fu and True); Research and Medical Service, St Louis VA Medical Center, St Louis (Drs True and Eisen); VA Palo Alto Health Care System, Palo Alto, Calif (Dr Jacob); Harvard Medical School Department of Psychiatry at Massachusetts Mental Health Center, Boston (Dr Tsuang); and the Department of Epidemiology, Harvard School of Public Health, Boston (Dr Tsuang).


REFERENCES
 Jump to Section
 •Top
 •Introduction
 •Methods
 •Results
 •Comment
 •Author information
 •References

1. Ross HE, Glaser FB, Germanson T. The prevalence of psychiatric disorders in patients with alcohol and other drug problems. Arch Gen Psychiatry. 1988;45:1023-1031. FREE FULL TEXT
2. Merikangas KR, Gelernter CS. Co-morbidity for alcoholism and depression. Psychiatr Clin North Am. 1990;13:613-632. ISI | PUBMED
3. Penick EC, Powell BJ, Nickel EJ, Bingham SF, Riesenmy KR, Reed MR, Campbell J. Comorbidity of lifetime psychiatric disorder among male alcoholic patients. Alcohol Clin Exp Res. 1994;18:1289-1293. FULL TEXT | ISI | PUBMED
4. Kessler RC, McGonagle KA, Zhao S, Nelson CB, Hughes M, Eshleman S, Wittchen H, Kendler KS. Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States: results from the National Comorbidity Survey. Arch Gen Psychiatry. 1994;51:8-19. FREE FULL TEXT
5. Kessler RC, Nelson CB, McGonagle KA, Liu J, Swartz M, Blazer DG. Comorbidity of DSM-III-R major depressive disorder in the general population: results from the US national comorbidity survey. Br J Psychiatry. 1996;168:17-30.
6. Kessler RC, Crum RM, Warner LA, Nelson CB, Schulenberg J, Anthony JC. Lifetime co-occurrence of DSM-III-R alcohol abuse and dependence with other psychiatric disorders in the national comorbidity survey. Arch Gen Psychiatry. 1997;54:313-321. FREE FULL TEXT
7. Regier DA, Farmer ME, Rae DS, Locke BZ, Keith SJ, Judd LL, Goodwin FK. Comorbidity of mental disorders with alcohol and other drug abuse: results from the Epidemiologic Catchment Area (ECA) Study. JAMA. 1990;264:2511-2518. FREE FULL TEXT
8. Grant BF, Harford TC. Comorbidity between DSM-IV alcohol use disorders and major depression: results of a national survey. Drug Alcohol Depend. 1995;39:197-206. FULL TEXT | ISI | PUBMED
9. Grant BF, Hasin DS, Dawson DA. The relationship between DSM-IV alcohol use disorders and DSM-IV major depression: examination of the primary-secondary distinction in a general population sample. J Affect Disord. 1996;38:113-128. FULL TEXT | ISI | PUBMED
10. Reich T, Cloninger CR, Lewis C, Rice J. Some recent findings from the study of genotype-environment interaction in alcoholism. NIAAA Res Monogr. 1981;5:145-164.
11. Yates WR, Petty F, Brown K. Factors associated with depression among primary alcoholics. Compr Psychiatry. 1988;29:28-33. FULL TEXT | ISI | PUBMED
12. Lewis CE, Rice J, Helzer JE. Diagnostic interactions: alcoholism and antisocial personality. J Nerv Ment Dis. 1983;171:105-113. ISI | PUBMED
13. Hesselbrock MN, Meyer RE, Keener JJ. Psychopathology in hospitalized alcoholics. Arch Gen Psychiatry. 1985;42:1050-1055. FREE FULL TEXT
14. Hesselbrock VM, Hesselbrock MN, Workman-Daniels KL. Effect of major depression and antisocial personality on alcoholism: course and motivational patterns. J Stud Alcohol. 1986;47:207-212. ISI | PUBMED
15. Hesselbrock MN. Gender comparison of antisocial personality disorder and depression in alcoholism. J Subst Abuse. 1991;3:205-219. PUBMED
16. Cadoret R, Troughton E, Widmer R. Clinical differences between antisocial and primary alcoholics. Compr Psychiatry. 1984;25:1-8. FULL TEXT | ISI | PUBMED
17. Cloninger CR, Sigvardsson S, Bohman M. Childhood personality predicts alcohol abuse in young adults. Alcohol Clin Exp Res. 1988;12:494-505. FULL TEXT | ISI | PUBMED
18. Holdcraft LC, Iacono WG, McGue MK. Antisocial personality disorder and depression in relation to alcoholism: a community-based sample. J Stud Alcohol. 1998;59:222-226. ISI | PUBMED
19. Johnson JG, Cohen P, Skodol AE, Oldham JM, Kasen S, Brook JS. Personality disorders in adolescence and risk of major mental disorders and suicidality during adulthood. Arch Gen Psychiatry. 1999;56:805-811. FREE FULL TEXT
20. Grant BF. Comorbidity between DSM-IV drug use disorders and major depression: results of a national survey of adults. J Subst Abuse. 1995;7:481-497. FULL TEXT | PUBMED
21. Kessler RC, Nelson CB, McGonagle KA, Edlund MJ, Frank RG, Leaf PJ. The epidemiology of co-occurring addictive and mental disorders: implications for prevention and service utilization. Am J Orthopsychiatry. 1996;66:17-31. ISI | PUBMED
22. Halikas JA, Goodwin DW, Guze SB. Marijuana use and psychiatric illness. Arch Gen Psychiatry. 1972;27:162-165. FREE FULL TEXT
23. Bell DS, Champion RA. Deviancy, delinquency and drug use. Br J Psychiatry. 1979;134:269-276. FREE FULL TEXT
24. Stefanis C, Liakos A, Boulougouris J, Fink M, Freedman AM. Chronic hashish use and mental disorder. Am J Psychiatry. 1976;133:225-227. FREE FULL TEXT
25. Weller RA, Halikas JA. Marijuana use and psychiatric illness: a follow-up study. Am J Psychiatry. 1985;142:848-850. FREE FULL TEXT
26. Cadoret RJ, O'Gorman TW, Heywood E, Troughton E. Genetic and environmental factors in major depression. J Affect Disord. 1985;9:155-164. FULL TEXT | ISI | PUBMED
27. Kendler KS, Neale MC, Kessler RC, Heath AC, Eaves LJ. A population-based twin study of major depression in women: the impact of varying definitions of illness. Arch Gen Psychiatry. 1992;49:257-266. FREE FULL TEXT
28. Kendler KS, Neale MC, MacLean CJ, Heath AC, Eaves LJ, Kessler RC. Smoking and major depression. Arch Gen Psychiatry. 1993;50:36-43. FREE FULL TEXT
29. Kendler KS, Prescott CA. A population-based twin study of lifetime major depression in men and women. Arch Gen Psychiatry. 1999;56:39-44. FREE FULL TEXT
30. Lyons MJ, Eisen SA, Goldberg J, True W, Lin N, Meyer JM, Toomey R, Faraone SV, Merla-Ramos M, Tsuang MT. A registry-based twin study of depression in men. Arch Gen Psychiatry. 1998;55:468-472. FREE FULL TEXT
31. Bierut LJ, Heath AC, Bucholz KK, Dinwiddie SH, Madden PA, Statham DJ, Dunne MP, Martin NG. Major depressive disorder in a community-based twin sample: are there different genetic and environmental contributions for men and women? Arch Gen Psychiatry. 1999;56:557-563. FREE FULL TEXT
32. Grove WM, Eckert ED, Heston L, Bouchard TJ, Segal N, Lykken DT. Heritability of substance abuse and antisocial behavior: a study of monozygotic twins reared apart. Biol Psychiatry. 1990;27:1293-1304. FULL TEXT | ISI | PUBMED
33. Slutske WS, Heath AC, Dinwiddie SH, Madden PA, Bucholz KK, Dunne MP, Statham DJ, Martin NG. Modeling genetic and environmental influences in the etiology of conduct disorder: a study of 2682 adult twin pairs. J Abnorm Psychol. 1997;106:266-279. FULL TEXT | ISI | PUBMED
34. Slutske WS, Heath AC, Dinwiddie SH, Madden PA, Bucholz KK, Dunne MP, Statham DJ, Martin NG. Common genetic risk factors for conduct disorder and AD. J Abnorm Psychol. 1998;107:363-374. FULL TEXT | ISI | PUBMED
35. O'Connor TG, McGuire S, Reiss D, Hetherington EM, Plomin R. Co-occurrence of depressive symptoms and antisocial behavior in adolescence: a common genetic liability. J Abnorm Psychol. 1998;107:27-37. FULL TEXT | ISI | PUBMED
36. Lyons MJ, Ture WR, Eisen SA, Goldberg J, Meyer J, Faraone SV, Eaves LJ, Tsuang MT. Differential heritability of adult and juvenile antisocial traits. Arch Gen Psychiatry. 1995;52:906-915. FREE FULL TEXT
37. Rowe DC. Biometrical genetic models of self-reported delinquent behavior: a twin study. Behav Genet. 1983;13:473-489. FULL TEXT | ISI | PUBMED
38. Cloninger CR, Gottesman II. Genetic and environmental factors in antisocial behavior disorders. In: Mednick SA, Moffitt TE, Stack SA, eds. The Causes of Crime: New Biological Approaches. New York, NY: Cambridge University Press; 1987:92-109.
39. Cloninger CR. Genetic and environmental factors in the development of alcoholism. J Psychiatr Treat Eval. 1983;5:487-496. ISI
40. Kendler KS, Heath AC, Neale MC, Kessler RC, Eaves LJ. Alcoholism and major depression in women: a twin study of the causes of comorbidity. Arch Gen Psychiatry. 1993;50:690-698. FREE FULL TEXT
41. McGue M. Genes, environment and the etiology of alcoholism. NIAAA Res Monogr. 1994;26:1-40.
42. Heath AC, Bucholz KK, Madden PAF. Genetic and environmental contributions to AD risk in a national twin sample: consistency of findings in men and women. Psychol Med. 1997;27:1381-1396. FULL TEXT | ISI | PUBMED
43. Heath AC, Madden PA, Bucholz KK, Dinwiddie SH, Slutske WS, Bierut LJ, Rohrbaugh JW, Statham DJ, Dunne MP, Whitfield JB, Martin NG. Genetic differences in alcohol sensitivity and the inheritance of alcoholism risk. Psychol Med. 1999;29:1069-1081. FULL TEXT | ISI | PUBMED
44. True WR, Xian H, Scherrer JF, Madden PAF, Bucholz KK, Heath AC, Eisen SA, Lyons MJ, Goldberg J, Tsuang MT. Common genetic vulnerability for nicotine and alcohol dependence in men. Arch Gen Psychiatry. 1999;56:655-661. FREE FULL TEXT
45. Prescott CA, Neale MC, Corey LA, Kendler KS. Predictors of problem drinking and AD in a population-based sample of female twins. J Stud Alcohol. 1997;58:167-181. ISI | PUBMED
46. Prescott CA, Aggen SH, Kendler KS. Sex differences in the sources of genetic liability to alcohol abuse and dependence in a population based sample of US twins. Alcohol Clin Exp Res. 1999;23:1136-1144. FULL TEXT | ISI | PUBMED
47. Slutske WS, True WR, Scherrer JF, Heath AC, Bucholz KK, Eisen SA, Oldberg J, Lyons MJ, Tsuang MT. The heritability of alcoholism symptoms: "indicators of genetic and environmental influence in alcohol dependent individuals" revisited. Alcohol Clin Exp Res. 1999;23:759-769. ISI | PUBMED
48. Lyons MJ, Toomey R, Meyer JM, Green AI, Eisen SA, Goldberg J, True WR, Tsuang MT. How do genes influence marijuana use? the role of subjective effects. Addiction. 1997;92:409-417. FULL TEXT | ISI | PUBMED
49. Tsuang MT, Lyons MJ, Eisen SA, Goldberg J, True W, Lin N, Meyer JM, Toomy R, Faraone SV, Eaves L. Genetic influences on DSM-III-R drug abuse and dependence: a study of 3372 twin pairs. Am J Med Genet. 1996;67:473-477. FULL TEXT | ISI | PUBMED
50. Tsuang MT, Lyons MJ, Meyer JM, Doyle T, Eisen SA, Goldberg J, True W, Lin N, Toomy R, Eaves L. Co-occurrence of abuse of different drugs in men. Arch Gen Psychiatry. 1998;55:967-972. FREE FULL TEXT
51. Kendler KS, Prescott CA. Cannabis use, abuse, and dependence in a population-based sample of female twins. Am J Psychiatry. 1998;155:1016-1022. FREE FULL TEXT
52. True WR, Heath AC, Scherrer JF, Xian H, Lin N, Eisen SA, Lyons MJ, Goldberg J, Tsuang MT. Interrelationship of genetic and environmental influences on conduct disorder and alcohol and marijuana dependence symptoms. Am J Med Genet. 1999;88:391-397. FULL TEXT | ISI | PUBMED
53. Cloninger CR, Reich T, Wetzel R. Alcoholism and affective disorders: familial associations and genetic models. In: Goodwin DW, Erickson CK, eds. Alcoholism and Affective Disorders: Clinical, Genetic and Biochemical Studies. New York, NY: Spectrum Publications; 1979:57-86.
54. Penick EC, Powell BJ, Bingham SF, Liskow BI, Miller NS, Read MR. A comparative study of familial alcoholism. J Stud Alcohol. 1987;48:136-146. ISI | PUBMED
55. Pitts FN, Winokur G. Affective disorder, VII: alcoholism and affective disorder. J Psychiatr Res. 1966;4:37-50.
56. Roy A, DeJong J, Lamparski D, George T, Linnoila M. Depression among alcoholics: relationship to clinical and cerebrospinal fluid variables. Arch Gen Psychiatry. 1991;48:428-432. FREE FULL TEXT
57. Winokur G, Rimmer J, Reich T. Alcoholism IV: is there more than one type of alcoholism? Br J Psychiatry. 1971;118:525-531. FREE FULL TEXT
58. Coryell W, Winokur G, Keller M, Scheftner W, Endicott J. Alcoholism and primary major depression: a family study approach to co-existing disorders. J Affect Disord. 1992;24:93-99. FULL TEXT | ISI | PUBMED
59. Gershon ES, Mark A, Cohen N, Belizon N, Baron M, Knobe K. Transmitted factors in the morbid risk of affective disorders: a controlled study. J Psychiatr Res. 1975;12:283-299. FULL TEXT | ISI
60. Gershon ES, Hamovit J, Guroff JJ, Dibble E, Leckman JF, Sceery W, Targum SD, Nurnberger JI, Goldin LR, Bunney WE. A family study of schizoaffective, bipolar I, bipolar II, unipolar, and normal control probands. Arch Gen Psychiatry. 1982;39:1157-1167. FREE FULL TEXT
61. Merikangas KR, Leckman JF, Prusoff BA, Pauls DL, Weissman MM. Familial transmission of depression and alcoholism. Arch Gen Psychiatry. 1985;42:367-372. FREE FULL TEXT
62. Wender PH, Kety SS, Rosenthal D, Schulsinger F, Ortmann J, Lunde I. Psychiatric disorders in the biological and adoptive families of adopted individuals with affective disorders. Arch Gen Psychiatry. 1986;43:923-929. FREE FULL TEXT
63. Ingraham LJ, Wender PH. Risk for affective disorder and alcohol and other drug abuse in the relatives of affectively ill adoptees. J Affect Disord. 1992;26:45-52. FULL TEXT | ISI | PUBMED
64. Prescott CA, Aggen SH, Kendler KS. Sex-specific genetic influences on the comorbidity of alcoholism and major depression in a population-based sample of US twins. Arch Gen Psychiatry. 2000;57:803-811. FREE FULL TEXT
65. Goodwin DW, Schulsinger R, Hermansen L, Guze SB, Winokur G. Alcohol problems in adoptees raised apart from alcoholic biological parents. Arch Gen Psychiatry. 1973;28:238-255. FREE FULL TEXT
66. Goodwin DW, Schlusinger F, Knop J, Mednick S, Guze SB. Alcoholism and depression in adopted-out daughters of alcoholics. Arch Gen Psychiatry. 1977;34:751-755. FREE FULL TEXT
67. Pickens RW, Svikis DS, McGue M, LaBuda MC. Common genetic mechanisms in alcohol, drug and mental disorder comorbidity. Drug Alcohol Depend. 1995;39:129-138. FULL TEXT | ISI | PUBMED
68. Merikangas KR, Metha RL, Molnar BE, Walters EE, Swendsen JD, Aguilar-Gaziola S, Bijl R, Borges G, Caraveo-Anduaga JJ, Dewit DJ, Kolody B, Vega WA, Tittchen H, Kessler RC. Comorbidity of substance use disorders with mood and anxiety disorders: results of the international consortium in psychiatric epidemiology. Addict Behav. 1998;23:893-907. FULL TEXT | ISI | PUBMED
69. Rowe JB, Sullivan PF, Mulder RT, Joyce PR. The effect of a history of conduct disorder in adult major depression. J Affect Disord. 1996;37:51-63. FULL TEXT | ISI | PUBMED
70. Shea MT, Widiger TA, Klein MH. Comorbidity of personality disorders and depression: implications for treatment. J Consult Clin Psychol. 1992;60:857-868. FULL TEXT | ISI | PUBMED
71. Kendler KS, Davis CG, Kessler RC. The familial aggregation of common psychiatric and substance use disorders in the National Comorbidity Survey: a family history study. Br J Psychiatry. 1997;170:541-548. FREE FULL TEXT
72. Krueger RF. The structure of common mental disorders. Arch Gen Psychiatry. 1999;56:921-926. FREE FULL TEXT
73. Hirschfeld RM. Personality disorders and depression: comorbidity. Depress Anxiety. 1999;10:142-146. FULL TEXT | ISI | PUBMED
74. Hawkins JD, Catalano RF, Miller JY. Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: implications for substance abuse prevention. Psychol Bull. 1992;112:64-105. FULL TEXT | ISI | PUBMED
75. Eisen S, Newman R, Goldberg J, Rice J, True W. Determining zygosity in the Vietnam Era Twin Registry: an approach using questionnaires. Clin Genet. 1989;35:423-432. ISI | PUBMED
76. Eisen SA, True W, Goldberg J, Henderson W, Robinette CD. The Vietnam Era Twin (VET) Registry: method of construction. Acta Genet Med Gemellol. 1987;36:61-66. PUBMED
77. Henderson GH, Eisen SA, Goldberg J, True WR, Barnes JE, Vitek ME. The Vietnam Era Twin Registry: a resource for medical research. Public Health Rep. 1990;105:368-373. ISI | PUBMED
78. Goldberg J, True W, Eisen SA, Henderson W, Robinette CD. The Vietnam Era Twin (VET) Registry: ascertainment bias. Acta Genet Med Gemellol. 1987;36:67-78. PUBMED
79. Robins LN, Helzer JE, Cottler L, Goldring E. National Institute of Mental Health Diagnostic Interview Schedule, Version III, Revised. St Louis, Mo: Dept of Psychiatry, Washington University; 1988.
80. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Washington, DC: American Psychiatric Association; 1987.
81. Slutske WS, True WR, Scherrer JF, Bucholz KK, Heath AC, Eisen SA, Goldberg J, Lyons MJ, Tsuang MT. Long-term reliability and validity of alcoholism diagnoses and symptoms in a large national telephone interview survey. Alcohol Clin Exp Res. 1997;54:1126-1128.
82. Falconer DS. The inheritance of liability to certain disease, estimated from the incidence among relatives. Ann Hum Genet. 1965;29:51-76. FULL TEXT | ISI
83. Jöreskog KG, Sörbom D. PRELIS 2 User's Reference Guide. Chicago, Ill: Scientific Software International; 1993.
84. Neale MC, Maes HH. Methodology for Genetic Studies of Twins and Families. Dordrecht, the Netherlands: Kluwer Academic Publishers; 2000.
85. Xian H, Scherrer J, Eisen S, True W, Heath AC, Goldberg J, Lyons M, Tsuang MT. Self-reported zygosity and the equal environmental assumption for psychiatric disorders in the Vietnam Era Twin Registry. Behav Genet. 2000;30:303-310. FULL TEXT | ISI | PUBMED
86. Neale MC, Boker SM, Xie G, Maes HH. Mx: Statistical Modeling. 5th ed. Richmond: Dept of Psychiatry, Virginia Commonwealth University; 1999.
87. Akaike H. Factor analysis and AIC. Psychometrika. 1984;52:317-332. FULL TEXT
88. Williams LJ, Holahan PJ. Parsimony-based fit indices for multiple-indicator models: do they work? Struct Equation Model. 1994;1:161-189.
89. Burke KC, Burke JD, Rae DS, Regier DA. Comparing age at onset of major depression and other psychiatric disorders by birth cohorts in five US community populations. Arch Gen Psychiatry. 1991;48:789-795. FREE FULL TEXT
90. Bierut LJ, Dinwiddie SH, Begleiter H, Crowe RR, Hesselbrock V, Nurnberger JI Jr, Porjesz B, Schuckit MA, Reich T. Familial transmission of substance dependence: alcohol, marijuana, cocaine, and habitual smoking: a report from the Collaborative Study on the Genetics of Alcoholism. Arch Gen Psychiatry. 1998;55:982-988. FREE FULL TEXT
91. Iacono WG, Carlson STR, Taylor J, Elkins IJ, McGue M. Behavioral disinhibition and the development of substance-use disorders: findings from the Minnesota Twin Family Study. Dev Psychopathol. 1999;11:869-900. FULL TEXT | ISI | PUBMED
92. Merikangas KR, Stolar M, Stevens DE, Goulet J, Preisig MA, Fenton B, Zhang H, O'Malley SS, Rounsaville BJ. Familial transmission of substance use disorders. Arch Gen Psychiatry. 1998;55:973-979. FREE FULL TEXT
93. Jordan BK, Schlenger WE, Hough R, Kulka RA, Weiss D, Fairbank JA, Marmar CR. Lifetime and current prevalence of specific psychiatric disorders among Vietnam veterans and controls. Arch Gen Psychiatry. 1991;48:207-215. FREE FULL TEXT
94. Kendler KS, Prescott CA. Cannabis use, abuse, and dependence in a population-based sample of female twins. Am J Psychiatry. 1998;155:1016-1022.
95. Neale MC, Kendler KS. Models of comorbidity for multifactorial disorders. Am J Hum Genet. 1995;57:935-953. ISI | PUBMED


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter     What's this?

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Depressed Mood in Childhood and Subsequent Alcohol Use Through Adolescence and Young Adulthood
Crum et al.
Arch Gen Psychiatry 2008;65:702-712.
ABSTRACT | FULL TEXT  

Specificity of Bipolar Spectrum Conditions in the Comorbidity of Mood and Substance Use Disorders: Results From the Zurich Cohort Study
Merikangas et al.
Arch Gen Psychiatry 2008;65:47-52.
ABSTRACT | FULL TEXT  

Exploring Risk Factors for the Emergence of Children's Mental Health Problems.
Essex et al.
Arch Gen Psychiatry 2006;63:1246-1256.
ABSTRACT | FULL TEXT  

Genetic Heterogeneity, Modifier Genes, and Quantitative Phenotypes in Psychiatric Illness: Searching for a Framework
Fanous and Kendler
Focus 2006;4:423.
ABSTRACT | FULL TEXT  

Shared Genetic Contributions to Pathological Gambling and Major Depression in Men
Potenza et al.
Arch Gen Psychiatry 2005;62:1015-1021.
ABSTRACT | FULL TEXT  

Maternal Depression and Children's Antisocial Behavior: Nature and Nurture Effects
Kim-Cohen et al.
Arch Gen Psychiatry 2005;62:173-181.
ABSTRACT | FULL TEXT  

Major Depressive Disorder, Suicidal Ideation, and Suicide Attempt in Twins Discordant for Cannabis Dependence and Early-Onset Cannabis Use
Lynskey et al.
Arch Gen Psychiatry 2004;61:1026-1032.
ABSTRACT | FULL TEXT  

Family Transmission and Heritability of Externalizing Disorders: A Twin-Family Study
Hicks et al.
Arch Gen Psychiatry 2004;61:922-928.
ABSTRACT | FULL TEXT  

Alcohol & Drug Abuse: Drug Policy by Analogy: Well, It's Like This...
Marlowe and DeMatteo
Psychiatr. Serv. 2003;54:1455-1456.
FULL TEXT  





HOME | CURRENT ISSUE | PAST ISSUES | TOPIC COLLECTIONS | SUBMIT | SUBSCRIBE | HELP
CONDITIONS OF USE | PRIVACY POLICY | CONTACT US | SITE MAP
 
© 2002 American Medical Association. All Rights Reserved.