Early-onset depressive disorders predict the use of addictive substances in adolescence / EurekAlert, 21 October 2008
http://www.eurekalert.org/pub_releases/2008-10/uoh-edd102108.php
"In a prospective study of over 1800 interviewed young Finnish twins, early-onset depressive disorders at age 14 significantly predicted daily smoking, smokeless tobacco use, frequent illicit drug use, frequent alcohol use and recurrent intoxication three years later, even among those adolescents who were not users at baseline."