The differential impact of risk factors on illicit drug involvement in females.
BACKGROUND
Initiation of drug use and progression to abuse/dependence involve complex pathways. Potential risk factors may correlate with initiation or progression or both. Are there risk factors that associate with illicit drug use or illicit drug abuse/dependence? Is the magnitude of the association the same for use and abuse/dependence? Does this pattern of association differ across categories of drugs?


METHODS
We used data from female-female adult twins to assess the association of 26 putative risk factors with use and abuse/dependence of six illicit psychoactive drugs. Drug involvement was represented by independent dichotomous outcomes and by a single ordinal variable. Odds ratios were obtained by logistic regression and a continuation ratio was used to test the magnitude of association.


RESULTS
Factors associate in similar patterns with different drug categories. Some associated factors interact only with initiation while others relate with both stages. There is a stronger association of significant socio-demographic factors with drug use while the psychiatric diagnoses are more strongly associated with progression to abuse/dependence.


CONCLUSIONS
Risk factors may be use-specific, abuse/dependence-specific or common to use and abuse/dependence. The trend of associations is similar across different illicit drugs. This suggests complex, interacting pathways that determine drug habits in individuals. These results are hypothesis-generating and future studies of causal relationships may draw from the outcomes presented in these analyses.
Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Dept. of Human Genetics, Richmond, VA, USA. arpana_vipbg@yahoo.com
Arpana
A
Agrawal
Charles O
CO
Gardner
Carol A
CA
Prescott
Kenneth S
KS
Kendler
D000293:Adolescent; D000328:Adult; D004200:Diseases in Twins / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D013287:Illicit Drugs; D008137:Longitudinal Studies; D001523:Mental Disorders / Q000453:epidemiology; D008875:Middle Aged; D012307:Risk Factors; D012959:Socioeconomic Factors; D013223:Statistics as Topic; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000209:etiology; D014768:Virginia
D013287:Illicit Drugs