Adolescents' self-defined tobacco use status, marijuana use, and tobacco dependence.

AIMS: To examine differences in tobacco use and dependence between adolescents who are and are not marijuana users.

DESIGN: Cross-sectional analysis of existing survey data.

PARTICIPANTS: Data were obtained from 7440 adolescents who completed the British Columbia Youth Survey of Smoking and Health II (BCYSOSH-II), a school based survey conducted in 2004.

MEASURES: Responses to demographic, current smoking, alcohol use, self-defined tobacco and marijuana use status questions, perceived physical and mental addiction to tobacco, modified-Fagerstrom Tolerance Questionnaire (M-FTQ), and the Dimensions of Tobacco Dependence Scale (DTDS) were obtained.

FINDINGS: Marijuana users were 5.9 times more likely to be current tobacco smokers and reported higher levels of perceived addiction to tobacco as compared with marijuana non-users. After controlling for demographics, life-time tobacco use, and alcohol use, marijuana use was associated with the nicotine dependent and sensory dimensions of tobacco dependence.

CONCLUSIONS: Adolescents who concurrently use tobacco and marijuana may be more tobacco dependent than are marijuana non-users. Concurrent use of marijuana may be a factor associated with tobacco dependence among a sub-group of concomitant drug-using adolescents.