Brief interventions prevent increased risk of depressive symptoms among teens, according to a University of Texas study.

"We were amazed that a brief exposure to the message that people can change, during a key transition - the first few weeks of high school - could prevent increases in symptoms of depression," psychological scientist and lead researcher David Scott Yeager said in a press release. "Yet finding anything promising has the potential to be important because prevention is far better than treatment - not only for financial reasons but also because it avoids human suffering."

Adolescence is a challenging transitional period marked by puberty, changes in friendship networks and status hierarchy. Major depression arises during this developmental period.

"When teens are excluded or bullied it can be reasonable to wonder if they are 'losers' or 'not likable,'" said Yeager. "We asked: Could teaching teens that people can change reduce those thoughts? And if so could it even prevent overall symptoms of depression?"

For the study, the researchers observed about 600 ninth graders across three different high schools. At the beginning of the school year in September, students were randomly assigned to the treatment intervention or a similar control activity, though they were not aware of the group assignment.

In the treatment intervention group, students read a passage about how individuals' personalities are subjected to change. In other words, being bullied is not the result of a fixed, personal deficiency, nor are bullies essentially "bad" people. After reading the passage, the students were asked to write a narrative on the same topic.

On the other hand, students in the control group read a passage that focused on the malleability of trait not related to personality: athletic ability.

After a follow-up of 9 months, clinically significant depressive symptoms increased by roughly 39 percent among students in the control group. Those in the intervention group reported no rise in depressive symptoms, even if they were bullied.

The researchers said that intervention effectively treated negative mood, feelings of ineffectiveness, and low self-esteem. These findings are promising as intervention requires little time and effort.

The finding is published in the Clinical Psychological Science Journal.