Optimism may help protect teens from depression, according to a study published in the journal Pediatrics and reported by U.S. News and World Report online.

The findings matter because 10 to 15 percent of adolescents experience symptoms of depression at any given time, which is a major risk factor for suicide, increased substance abuse risk, school and relationship troubles and physical illness.

For the 18-month study, researchers asked 5,634 Australian students, ages 12 and 13, about their mental state, substance abuse habits and antisocial behavior. Scientists found that the more optimistic students were, the less likely they were to become depressed. What’s more, optimistic teens were slightly less likely to commit criminal activity or practice heavy substance abuse—but just moderately so.

And what about teens who aren’t optimistic? They can learn how to see the brighter side of life, said Martin Seligman, PhD, a psychologist at the Positive Psychology Center at the University of Pennsylvania. What’s good about this is that optimism can make the ups and downs of the teen years less painful for parents and teens.

Click here to learn how looking on the bright side helps improve your health.