@article{abfc7536e0024090aa62415b856dd2a7,
title = "Genetic and environmental influences on transitions in drug use",
abstract = "Genetic and environmental factors influence drug abuse, but abuse represents the culmination of a sequence of events. Different levels of use may have different determinants and these determinants may differ across drug types. Approximately 3200 male-male twin pairs from the Vietnam Era Twin Registry were interviewed by telephone. Data were obtained regarding exposure to six categories of illicit drugs, initiation of use, continuation of use, regular usage, and diagnosis of drug abuse/dependence. Genetic, common environmental, and unique environmental influences on transitions of drug involvement, defined as movement from one level of drug use to the next, were investigated. Marijuana had the highest conditional probability for the transition from exposure to use, from use to use more than five times, and from use more than five times to regular use. The rate of transition to regular use of heroin was higher than the rate for amphetamine, cocaine, sedatives, and psychedelics. Cocaine had the highest conditional probability for the transition from regular use to abuse/dependence. Significant genetic influences were observed for a number of transitions in marijuana, amphetamine, and cocaine usage.",
keywords = "Drug abuse, Drug dependence, Drug transitions, Environmental, Genetic, Twins",
author = "Tsuang, \{Ming T.\} and Lyons, \{Michael J.\} and Harley, \{Rebecca M.\} and Hong Xian and Seth Eisen and Jack Goldberg and True, \{William R.\} and Faraone, \{Stephen V.\}",
note = "Funding Information: This work was supported by a grant (DA04604) from the National Institute of Drug Abuse to Dr. Ming T. Tsuang and the Department of Veterans Affairs Health Services Research and Development Service and Cooperative Studies Program (Study 1992). Department of Veterans Affairs: (1) Midwest Center for Health Services \& Policy Research—Vietnam Era Twin Registry Director, William G. Henderson, Ph.D.; Epidemiologist, Jack Goldberg, Ph.D.; Registry Programmer, Kenneth Bukowski; Coordinator, Mary Ellen Vitek; and Statistical Assistant, Rita Havlicek; (2) VET Registry Advisory Committee—E. Coccaro, M.D., Ph.D., Theodore Colton, Sc.D., Walter E. Nance, M.D., Ph.D., Ralph S. Paffenbarger, Jr., M.D., Dr. P.H., Myrna Weissman, Ph.D., and Roger R. Williams, M.D. (past); (3) VA. Headquarters—Chief Research \& Development Officer, John R. Feussner, M.D., Staff Assistant, Ping Huang, Ph.D., Program Assistant, Joseph Gough; Health Services Research \& Development Service— Director, John Demakis, M.D.; Deputy Director, Shirley Meehan, M.B.A., Ph.D.; and Program Manager, Charles Welch, III, Ph.D. We also acknowledge Drs. Irv Gottesman of University of Virginia and Jag Khalsa of NIDA, whose contributions helped us to complete this project successfully. We thank John Simpson, Ph.D., and Jerry Fleming, M.S., for helpful comments on early drafts of this paper. Most importantly, the authors wish to acknowledge and thank the members of the Vietnam Era Twin Registry for their participation and cooperation. They willingly provided sensitive information and considerable time in responding to the survey. Without their contribution, this research project would not have been possible.",
year = "1999",
doi = "10.1023/A:1021635223370",
language = "English",
volume = "29",
pages = "473--479",
journal = "Behavior genetics",
issn = "0001-8244",
number = "6",
}