Objective: To examine the effects of sociodemographic, family, and peer predictors on the developmental patterns of illicit drug initiation from ages 12 to 21 years.
Method: A gender-balanced, ethnically diverse urban sample of 808 children in Seattle was surveyed at age 10 in 1985 and followed prospectively to age 21 in 1996. Discrete-time survival analysis was used to assess the effects of sociodemographic, family, and peer factors on the risk of initiation.
Results: The risk for initiating illicit drug use increased steadily from ages 12 to 21. High family conflict, low family bonding, and high peers' antisocial activities predicted higher risk of initiation across this developmental period. The effect of family bonding began to decline after age 18, while the effect of peers' antisocial activities began to increase after age 15. Few gender and ethnic differences were found.
Conclusions: Prevention programs need to include family and peer factors as important targets. Parents should create a warm and supportive family environment with appropriate supervision and control throughout adolescence. Association with antisocial peers should be reduced, especially in high school. Interventions addressing these family and peer factors should have beneficial effects across gender and ethnic groups.