Many young people behave in a delinquent fashion including using illegal drugs and committing minor offences such as shoplifting and vandalism but most grow out of this as they leave home, set up with a partner and get a job. Few studies have looked into the effect of these life changes on the use of drugs so a team of researchers from the RAND corporation in California followed 196 boys who had had residential treatment for substance abuse. The boys were between 13 and 17 at the start of the study and were surveyed after 3, 6, 12, 24, 30, 72 and 87 months. The study found that living independently and cohabiting were both associated with decreased substance abuse problems. Living with children was associated with more interpersonal violence (hitting people or getting into a fight). Living away from their parents was associated with an increase in substance problems as the boys moved into adulthood but a decrease thereafter suggesting that leaving the family home either too early or too late increased the risk of substance abuse.
D'Amico, Elizabeth J., Ramchand, Rajeev and Miles, Jeremy N.V. - Seven years later: developmental transitions and delinquent behavior for male adolescents who received long-term substance treatment Journal of Studies on Alcohol and Drugs September 2009, 70(5), 641-651