Level of current and past adolescent cigarette smoking as predictors of future substance use disorders in young adulthood.

AIMS: This study examined the impact of adolescent cigarette smoking (life-time use, recency, frequency and age of onset) on the occurrence of substance use disorders during young adulthood.
DESIGN: Participants were assessed while in high school (T1), approximately 1 year later (T2) and then after they had turned 24 years of age (T3).
SETTING: Adolescents were randomly selected at T1 from nine senior high schools in western Oregon. PARTICIPANTS: A subset (n = 684) of 1709 adolescents who had been assessed regarding cigarette smoking during high school were evaluated for alcohol, cannabis and other drug abuse/dependence up to age 24. MEASUREMENTS: Semi-structured interviews provided information regarding life-time use of cigarettes and chewing tobacco, age of smoking onset, frequency and quantity of cigarette smoking and quit efforts in adolescence. Diagnoses of substance abuse and dependence in young adulthood were made as per DSM-IV.
FINDINGS: Life-time smoking among older adolescents significantly increased the probability of future alcohol, cannabis, hard drug and multiple drug use disorders during young adulthood. Having been a former smoker did not reduce the risk of future substance use disorder, although having maintained smoking cessation for more than 12 months was associated with significantly lower rates of future alcohol use disorder. Daily smoking was associated with increased risk of future cannabis, hard drug and multiple drug use disorders. Among daily smokers, earlier smoking onset age predicted future substance use disorders.
CONCLUSIONS: The results extend knowledge about relationships between cigarette smoking during adolescence and the development of substance use disorders during young adulthood, illustrating additional risks associated with early cigarette smoking. Future research is needed to examine potential causal associations.