Environmental factors selectively impact co-occurrence of problem/pathological gambling with specific drug-use disorders in male twins.
OBJECTIVE
Multiple forms of drug abuse/dependence frequently co-occur with problem/pathological gambling (PPG). The current study examines the extent to which genetic and environmental factors contribute to their co-occurrence.


METHODS
Bivariate models investigated the magnitude and correlation of genetic and environmental contributions to problem/pathological gambling and its co-occurrence with nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence.


METHODS
Computer-assisted telephone interviews in the community.


METHODS
Participants were 7869 male twins in the Vietnam Era Twin Registry, a USA-based national twin registry.


METHODS
Life-time DSM-III-R diagnoses for problem/pathological gambling, nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence were determined using the Diagnostic Interview Schedule.


RESULTS
All drug-use disorders displayed additive genetic and non-shared environmental contributions, with cannabis abuse/dependence also displaying shared environmental contributions. Both genetic [genetic correlation rA  = 0.22; 95% confidence interval (CI) = 0.10-0.34] and non-shared environmental components (environmental correlation rE  = 0.24; 95% CI = 0.10-0.37) contributed to the co-occurrence of problem/pathological gambling and nicotine dependence. This pattern was shared by cannabis abuse/dependence (rA  = 0.32; 95% CI = 0.05-1.0; rE  = 0.36; 95% CI = 0.16-0.55) but not stimulant abuse/dependence (SAD), which showed only genetic contributions to the co-occurrence with problem/pathological gambling (rA  = 0.58; 95% CI = 0.45-0.73).


CONCLUSIONS
Strong links between gambling and stimulant-use disorders may relate to the neurochemical properties of stimulants or the illicit nature of using 'hard' drugs such as cocaine. The greater contribution of environmental factors to the co-occurrence between problem/pathological gambling and 'softer' forms of drug abuse/dependence (cannabis, tobacco) suggest that environmental interventions (perhaps relating to availability and legality) may help to diminish the relationship between problem/pathological gambling and tobacco- and cannabis-use disorders.
Research Service 151-JC, St Louis VAMC, St Louis, MO, USA; Department of Biostatistics, St Louis University School of Public Health, St Louis, MO, USA.
Hong
H
Xian
Justine L
JL
Giddens
Jeffrey F
JF
Scherrer
Seth A
SA
Eisen
Marc N
MN
Potenza
D000328:Adult; D019969:Amphetamine-Related Disorders / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D019970:Cocaine-Related Disorders / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D015897:Comorbidity; D005715:Gambling / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D059647:Gene-Environment Interaction; D006801:Humans; D016015:Logistic Models; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D001523:Mental Disorders / Q000235:genetics* / Q000523:psychology; D008875:Middle Aged; D012931:Social Environment; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D014029:Tobacco Use Disorder / Q000453:epidemiology / Q000235:genetics* / Q000523:psychology; D014429:Twins, Dizygotic / Q000235:genetics* / Q000523:psychology / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000235:genetics* / Q000523:psychology / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology
Amphetamine; cannabis; cocaine; nicotine dependence; pathological gambling