The study also revealed that parents, who themselves had personal problems or were using alcohol more frequently, were less likely to be aware of extent of use by younger teens and of their children's use.
For a six-month reporting period, 82 percent of parents accurately evaluated the presence of teen cigarette smoking; the parents' reports corresponded with the teens' reports of their own smoking.
Eighty-six percent of parents accurately evaluated the presence of teen alcohol use, and 86 percent accurately reported the presence of teen marijuana use. However, only 72 percent of the parents in the RIA study accurately reported the presence of illicit drug use (other than marijuana) by teens.
"This study begins to dispel the notion that parents don't know the extent to which their teens are using cigarettes, alcohol and illicit drugs. It seems that, despite a few exceptions, many parents do know the extent of their teenager's substance use," lead researcher Neil B. McGillicuddy, Ph.D., said.
"Parents can use this knowledge to help themselves cope with teenage substance use and the resulting stress on the family, as well as to begin conversations with their teen about making changes," he added.
For the study, 75 parents and their teenagers were interviewed separately about the teens' recent use of cigarettes, alcohol, marijuana and other illicit drugs. Parent-participants were, on average, female (85 percent), 39 years of age with 13 years of education. Teen-participants were, on average, male (61 percent), 16 years of age and not receiving substance abuse treatment (76 percent).
When parents' and teens' reports were discrepant, parents provided lower estimates of substance use than teens. That is, teens tended to report greater frequency and amount of substance use. Although some of these discrepancies were small (for instance regarding how often teens drank alcohol), others were substantial (parents were nearly twice as likely to underestimate the frequency of marijuana use and the quantity of alcohol use).
In addition, McGillicuddy and colleagues set out to find factors that might explain the discrepancies in parent-teen reports of teen substance use. Parents were less aware of the extent of the teen's substance use if the teen was younger (about 14 or 15), and if the parents did less monitoring of what their teens were doing after school, during the evening and on weekends.
McGillicuddy said that together, these findings suggest that parents need to consider increasing their monitoring of how teens spend their time and begin thinking about substance use at a significantly younger age.
"What we would hope that people come away with from this study, is that parents can be more aware of their teen's substance use, by reducing their own alcohol use, giving more attention to what their teen is doing 24/7, particularly if the teen is younger, and taking steps to reduce their own psychological distress," he said.
"Participation in parenting programs, especially those geared toward coping with an adolescent's substance use, can give the parent important skills to deal with teen behavior and have been found to reduce the parent's distress," he added.