CBT is designed to help patients understand how their thoughts and attitudes affect how they feel and how they respond to situations.
“What was exciting was the sustained effect over the length of the follow-up,” said lead author Dr. William R. Beardslee of the psychiatry department at Boston Children’s Hospital.
In a previous finding, Beardslee and his team found that at-risk teens still had a reduced risk of depression nine months after they began cognitive-behavioral therapy sessions. The study involved 316 teenagers of parents with current or past depressive disorders.
Now, two years later, the risk for depression is still reduced.
During the study, half of the teens were assigned to group therapy — eight weekly 90-minute group sessions with a trained therapist followed by six monthly sessions; the rest of the teens received standard care. The kids had symptoms of depression, but not diagnosable depressive disorders.
Depressive episodes — symptoms of depression lasting at least two weeks — were reported by the kids and their parents.
During the study and the two-year follow-up period, 37 percent of kids who received the group therapy sessions had at least one depressive episode, compared to 48 percent of those in the standard care group.
This difference, however, was found only among teens whose parents were not clinically depressed when the study began.
Specifically, if the parents were not depressed at the time of the study, group therapy prevented one depressive episode for every six kids in the program. However, for kids with currently depressed parents, therapy sessions didn’t seem to have an effect.
“First, we need to understand how current parental depression is related to differential outcomes,” Beardslee said. “Then, we need to target these factors to reduce their effects on child outcome.”
Of all other strategies to prevent depression, only a handful have demonstrated effectiveness one year after the intervention, said Dr. Irwin Sandler, a psychology professor and director of the Prevention Research Center at Arizona State University in Tempe.
“The current study is one of very few recent studies to extend that finding to 33 months—a very exciting and hopeful development,” he said.
The sessions seem to be cost-effective based on other evidence, Beardslee said, but most teens have an easier time accessing the therapy if they are already depressed rather than as a prevention of depression.
Cognitive-behavioral therapy is a very effective treatment, so it wasn’t surprising to see it work for prevention, said Myrna Weissman, Ph.D., a highly regarded researcher and professor of epidemiology in psychiatry at Columbia University in New York, who was not involved in the study.
“I’m also not surprised a depressed parent impeded prevention,” which reinforces the need for depressed parents to get treatment too, she said.
Source: JAMA Psychiatry