[A longitudinal study of the trajectories of deviant behavior among junior high school students].

This study investigated the trajectories and related factors of deviant behavior among students during their three years of junior high school. Data was analyzed from 344 students who completed a questionnaire survey every September. Nineteen categories of deviant behavior were examined, such as smoking, drinking alcohol, bullying, truancy, violence, and stealing. We determined behavioral trajectories from mild deviant behaviors to more serious ones. The data showed that more than half of the children who engaged in serious deviant behaviors in the third year followed a trajectory from mild deviant behaviors. The three factors of "deviant peers", "attachment to parents" and "achievement" were related to the trajectory into more serious deviant behaviors.