Researchers say they have found a link between teenage depression and the use of recreational drugs such ecstasy and speed.
Teenagers who use the drugs, also known as MDMA, methamphetamines or amphetamines, had nearly double the chance of suffering from depression, even long after they take the substances.
Researchers said that this does not prove that there is a causal link between the drugs and depression as those using the drugs may have already been more susceptible to mental illness.
"This doesn't ensure causality, but that's the closest we can get with this kind of study," said study co-author Dr. Jean-Sebastien Fallu, associate professor of educational psychology at the University of Montreal, reported CNN.
According to CBS News, researchers interviewed 3,900 10th grade students in Quebec and then followed up with them in the 11th grade.
Those teenagers who said they had used the drugs were 60 to 70 percent more likely to have depression symptoms about a year after admitting to using the substances.
Teens who used both drugs were also at a far higher risk of depression said the study.
"Many recreational users engage in simultaneous drug mixing, and these users may be particularly at risk of developing negative affective consequences," the study said, according to PostMedia News.
The researchers concluded that these drugs may have a modest impact on depression and urged further study to see if the substances acted harmfully on the brain, said Medical News Today.
The study was published online in the Journal of Epidemiology and Community Health.