Kids of depressed parents have an increased likelihood of becoming depressed, too, but group therapy sessions may help reduce that risk, according to a new study.

“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.

He and his coauthors had previously found a reduced risk of depression nine months after the cognitive behavioral therapy sessions began. The new results show that risk was still reduced two years after they ended.

The study included 316 teenagers of parents with current or past depressive disorders.

Half were assigned to the therapy program, which involved eight weekly 90-minute group sessions with a trained therapist followed by six monthly sessions, and the other half received standard care. The kids had symptoms of depression, but not diagnosable depressive disorders.

The researchers tracked teens’ “depressive episodes” lasting at least two weeks, as reported by the kids and their parents.

During the study and the two-year follow-up period - a total of 33 months - 37 percent of kids assigned to the therapy sessions had at least one depressive episode, versus 48 percent of those in the comparison group.

But that difference was only seen among teens whose parents were not clinically depressed when the study began.

When parents were not depressed at the time of the study, cognitive behavioral therapy prevented one depressive episode for every six kids in the program, the researchers found. However, for kids with currently depressed parents, therapy sessions didn’t seem to have an effect, they wrote in JAMA Psychiatry.

“First, we need to understand how current parental depression is related to differential outcomes,” Beardslee told Reuters Health. “Then, we need to target these factors to reduce their effects on child outcome.”

“The next step is to learn more about how to target programs like this to populations who can most benefit and to develop and test systems to deliver such programs effectively to the public,” said Irwin Sandler, a psychology professor and director of the Prevention Research Center at Arizona State University in Tempe.

Of all other strategies to prevent depression, only a handful have demonstrated effectiveness one year after the intervention, Sandler, who didn’t participate in the new research, said.

“The current study is one of very few recent studies to extend that finding to 33 months, a very exciting and hopeful development,” he told Reuters Health.

Cognitive behavioral therapy is designed to help patients understand how their thoughts and attitudes affect how they feel and how they respond to situations - then addresses practical steps they can take to improve negative thoughts and outcomes.

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 than for prevention of depression.

Cognitive behavioral therapy is a very effective treatment so it wasn’t surprising to see it work for prevention, according to Myrna Weissman, a 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 told Reuters Health.

SOURCE: JAMA Psychiatry, online September 4, 2013.

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