Alcohol dependence with comorbid drug dependence: Genetic and phenotypic associations suggest a more severe form of the disorder with stronger genetic contribution to risk

Danielle M. Dick, Arpana Agrawal, Jen C. Wang, Anthony Hinrichs, Sarah Bertelsen, Kathleen K. Bucholz, Marc Schuckit, John Kramer, John Nurnberger, Jay Tischfield, Howard J. Edenberg, Alison Goate, Laura J. Bierut

Research output: Contribution to journalArticle

68 Scopus citations

Abstract

Background: Twin data suggest that alcohol dependence comorbid with illicit drug dependence represents a more heritable form of the disorder. In the Collaborative Study on the Genetics of Alcoholism sample, approximately half the alcohol-dependent individuals also meet diagnostic criteria for illicit drug dependence. In this study, we tested for heterogeneity in the association between the muscarinic acetylcholine M2 receptor gene (CHRM2) and alcohol dependence, reported previously in the full sample, among the subgroups of alcohol-dependent individuals with and without comorbid drug dependence. Methods: Family-based association tests were conducted separately (a) in individuals with alcohol dependence with comorbid drug dependence (n = 477) and (b) in individuals with alcohol dependence without comorbid drug dependence (n = 433). These subgroups were subsequently compared on other phenotypic characteristics. Results: The evidence for association between CHRM2 and alcohol dependence came entirely from the subgroup of individuals with comorbid drug dependence. There was no evidence of association with CHRM2 among the alcohol-dependent individuals without drug dependence. Subsequent phenotypic analyses suggest that the subgroup of alcohol-dependent individuals with comorbid drug dependence differ on a number of other phenotypic characteristics, including several measures of the severity of their alcohol problems, personality traits and comorbid psychiatric disorders. Conclusions: These analyses provide specific genetic evidence suggesting that alcohol dependence with comorbid drug dependence represents a particularly severe form of the disorder, with higher genetic contribution to vulnerability.

Original languageEnglish (US)
Pages (from-to)1131-1139
Number of pages9
JournalAddiction
Volume102
Issue number7
DOIs
StatePublished - Jul 1 2007

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Keywords

  • Alcohol dependence
  • CHRM2
  • Comorbid drug dependence
  • Genetics
  • Heterogeneity

ASJC Scopus subject areas

  • Medicine (miscellaneous)

Cite this

Dick, D. M., Agrawal, A., Wang, J. C., Hinrichs, A., Bertelsen, S., Bucholz, K. K., Schuckit, M., Kramer, J., Nurnberger, J., Tischfield, J., Edenberg, H. J., Goate, A., & Bierut, L. J. (2007). Alcohol dependence with comorbid drug dependence: Genetic and phenotypic associations suggest a more severe form of the disorder with stronger genetic contribution to risk. Addiction, 102(7), 1131-1139. https://doi.org/10.1111/j.1360-0443.2007.01871.x