For the purposes of the present study, 157 (85%) of the original adolescents provided data on levels of substance use at the age 15 assessment (M age = 15.2, SD =.81) and 148 provided data on substance use at the age 16 assessment (M age = 16.3, SD = .87). These adolescents were also assessed at ages 13 in observed interactions with their mothers, and with analogue measures of social skills at ages 13 to 15.
