"Compared to teens who say their parents know a great deal or a fair amount about what’s really going on in their lives, teens who say their parents know very little or nothing at all are (Figure B):
"• One and a half times likelier to have used marijuana (21 percent vs. 13 percent); and
"• One and a half times likelier to have used alcohol (40 percent vs. 24 percent)."

Source

National Center on Addiction and Substance Abuse (CASA), "The Importance of Family Dinners VIII: A CASAColumbia White Paper," September 2012, p. 20.
http://www.casacolumbia.org/a…