Psychological Medicine



Original Article

DSM-IV alcohol dependence: a categorical or dimensional phenotype? 1


DEBORAH S. HASIN a1a2, XINHUA LIU a3, DONALD ALDERSON a2 and BRIDGET F. GRANT a4c1
a1 Department of Epidemiology, Mailman School of Public Health, and Department of Psychiatry, College of Physicians and Surgeons, Columbia University, NY, USA
a2 New York State Psychiatric Institute, New York, NY, USA
a3 Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, USA
a4 Laboratory of Epidemiology and Biometry, Division of Intramural Research, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA

Article author query
hasin ds   [PubMed][Google Scholar] 
liu x   [PubMed][Google Scholar] 
alderson d   [PubMed][Google Scholar] 
grant bf   [PubMed][Google Scholar] 

Abstract

Background. Etiologic research on complex disorders including alcohol dependence requires informative phenotypes. Information is lost when categorical variables represent inherently dimensional conditions. We investigated the validity of DSM-IV alcohol dependence as a dimensional phenotype by examining evidence for linearity and thresholds in associations with validating variables.

Method. Current drinkers in the National Longitudinal Alcohol Epidemiologic Survey (NLAES) (n=18352) and National Epidemiologic Survey of Alcohol and Related Conditions (NESARC) (n=20836) were analyzed. Validating variables included family alcoholism, early-onset drinking, and alcohol treatment. Logistic or Poisson regression modeled the relationships between the validating variables and dependence in categorical, dimensional or hybrid forms, with severity defined as number of current DSM-IV alcohol-dependence criteria. Wald tests assessed differences between models.

Results. No evidence was found for boundaries between categories. Instead, the association of alcohol dependence with the validating variables generally increased in linear fashion as the number of alcohol-dependence criteria increased. For NLAES models of family alcoholism, early-onset drinking and treatment, the lines had zero intercepts, with slopes of 0·18, 0·27, 0·70, respectively. For NESARC models of family history and early-onset drinking, the zero intercept lines had slopes of 0·20, 0·33, and 0·77, respectively. Wald tests indicated that models representing alcohol dependence as a dimensional linear predictor best described the association between dependence criteria and the validating variables.

Conclusions. The sample sizes allowed strong tests. Diagnoses are necessary for clinical decision-making, but a dimensional alcohol-dependence indicator should provide more information for research purposes.

(Published Online October 12 2006)


Correspondence:
c1 Laboratory of Epidemiology and Biometry, Room 3077, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, M.S. 9304, 5635 Fishers Lane, Bethesda, MD 20892-9304, USA. (Email: bgrant@willco.niaaa.nih.gov)


Footnotes

1 The views and opinions expressed in this report are those of the authors and should not be construed to represent the views of any of the sponsoring organizations, agencies, or the U.S. government.



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