By Robert Preidt
About 20 percent of U.S. high schools have drug testing, but this approach is controversial because there's little evidence that it works, the study authors said.
Of the 361 students in the new study, one-third went to schools that had a drug-testing policy. The researchers followed the students for a year and found that those in schools with drug testing were no less likely than other students to try marijuana, cigarettes or alcohol.
The findings are published in the January issue of the Journal of Studies on Alcohol and Drugs.
"Even though drug testing sounds good, based on the science, it's not working," study author Daniel Romer, of the University of Pennsylvania Annenberg Public Policy Center, said in a journal news release.
The students in the study were also asked about their school environment. Schools considered to have a positive environment had clear rules, and teachers and students treated each other with respect, the investigators found.
During the year of follow-up, students in schools with positive environments were about 20 percent less likely to try marijuana and 15 percent less likely to smoke cigarettes, compared to students in other schools.
However, a positive school environment did not seem to reduce the risk of student drinking. This may be due to the fact that drinking is considered more normal than drug use or smoking, Romer suggested.
"The whole culture uses alcohol," he said in the news release. "And you're fighting something that has widespread marketing behind it."