Substance abuse has trended upward among American teens over the past three years after a decade of declines, according to a report issued on Wednesday by the Partnership at Drugfree.org.

It said marijuana and ecstasy use among teens shows marked increases while attitudes toward alcohol use have become more relaxed.

The study, sponsored by MetLife Foundation and the 22nd in an annual series, found that between 2008 and 2010 teens who said they had used marijuana in the past year climbed to 39 percent from 32 percent.

Between 2008 and 2010, teens who said they had used the "party" drug ecstasy in the past year increased to 10 percent from six percent.

The Partnership Attitude Tracking Study, which based its findings on a survey of around 2,500 high school students, found that 45 percent said they do not see a "great risk" in heavy daily drinking, while 31 percent strongly disapprove of their peers getting drunk.

A total of 68 percent of those surveyed said they had had at least one drink in their lifetimes. Among them, the average age for that drink was 14.

Sean Clarkin, director of strategy for the Partnership at Drugfree.org, which last year changed its name from the Partnership for a Drug Free America, said the normalization of drug use in social media, the proliferation and discussion of medical marijuana, and budget cuts to substance abuse prevention programs have contributed to the rise of substance use and abuse.

"There are very high levels of kids reporting that they are using drugs and alcohol to deal with stress," Clarkin told Reuters in a phone interview, adding that the struggles families face in the current economy could be a factor in that.

"The net impact of all that puts an even heavier burden on parents who really need to play a active roll in preventing this behavior and knowing how to get help for a kid when they are abusing any of these substances," Clarkin said.