Latent transition analysis with covariates: pubertal timing and substance use behaviours in adolescent females.

We investigate the impact of pubertal development, age, and its interaction on female substance use behaviour. An extended latent transition model with two latent variables is used to reflect the dependency of adolescent substance use on pubertal development and age. A sample of females in grades 7-12 is analysed using maximum-likelihood estimation. Analyses indicate that experiencing puberty is related to increased substance use for all age groups. Among females aged 12-15, those who have experienced puberty are more likely to advance in substance use compared to their late-maturing counterparts. Particularly, among 12-year old non-substance users, those who have experienced puberty are approximately three times more likely to advance towards substance use than those who have not experienced puberty. In addition, among older females, those whose puberty is in progress are more prone to advance in substance use compared to those whose puberty has not occurred. Copyright 2005 John Wiley & Sons, Ltd.