A new study has heartening news for depressed adolescents who have not responded to initial treatment with drugs such as Paxil and Prozac.

Switching to another antidepressant may help, particularly if the patient also receives a type of psychotherapy known as cognitive behavioral therapy, according to the study, led by a University of Pittsburgh researcher and funded by the National Institute of Mental Health.

The findings were published today in the Journal of the American Medical Association.

"These findings should be encouraging for families with a teen who has been struggling with depression for some time," said Dr. David Brent, the study's lead author and a professor at the Pitt School of Medicine.

Even if a first treatment attempt is unsuccessful, other medications or treatment combinations are "likely to result in improvement," said Dr. Brent, who is also academic chief of child and adolescent psychiatry at Western Psychiatric Institute & Clinic.

Adolescent depression is a common condition that can cause problems in school or interpersonal relationships and increase the risk for suicidal behavior. By the time adolescents reach 18, they have about a one in five chance of having a depressive episode, Dr. Brent said.

Clinical guidelines recommend treatment with a drug from a class known as selective serotonin reuptake inhibitors, or SSRIs; psychotherapy; or both, the researchers noted.

Yet at least 40 percent of adolescents with depression do not show an adequate response to initial treatment, and studies have been lacking to guide follow-up care.

To address that issue, Dr. Brent and his colleagues conducted a randomized controlled trial of 334 patients 12 to 18 years old at six U.S. academic centers and community clinics from 2000 to 2006. Participants had a primary diagnosis of major depressive disorder that had not responded to initial treatment with an SSRI.

The class of drugs increases levels of the brain chemical serotonin by preventing nerve cells from reabsorbing it. Commonly prescribed drugs from the group include fluoxetine, paroxetine and citalopram -- also known, respectively, by the brand names Prozac, Paxil and Celexa.

Participants were randomly assigned to 12 weeks of treatment with one of four therapies: a switch to another SSRI; a switch to the drug venlafaxine, also known as Effexor, which had been shown in some studies to be better than an SSRI for treatment-resistant adult depression; a switch to an SSRI with cognitive behavior therapy, also known as CBT; or a switch to Effexor with CBT. The psychotherapy helps patients recognize negative patterns of thinking and reacting, then replace them with more productive alternatives.

Researchers found that 54.8 percent of study participants showed an adequate clinical response to a switch to either an SSRI or Effexor with CBT, compared with 40.5 percent who had a medication change alone. There was no difference in the response rate between Effexor and another SSRI.

Researchers noted that the beneficial effect from CBT was obtained with relatively few treatment sessions. On average, participants received about nine sessions.

They also noted that the study included patients with suicidal thoughts. While such adolescents are typically not used in studies, including them may make the findings more similar to doctors' experiences in the community, where suicidal behavior is a common reason for initiating psychiatric treatment.

The study provides "the kind of data parents and physicians need to make informed decisions about treatment options," said David Fassler, a professor of psychiatry at the University of Vermont College of Medicine.

The findings underscore "the importance of altering or modifying treatment based on an ongoing assessment of clinical response," said Dr. Fassler, who is also a board member for Mental Health America, a leading advocacy group.

For young people who don't respond to a medication change with CBT, other treatment options remain available, said Dr. Gary Swanson, medical director of child and adolescent psychiatry at Allegheny General Hospital.

The possibility of other medical problems or substance abuse should also be considered, he said.

The study indicated that recruitment of participants became more difficult after concerns were raised about use of SSRIs and other antidepressants in young people. In 2004, the U.S. Food and Drug Administration directed that "black box" warnings be placed on the drugs after a review found young people treated with antidepressants had a slightly elevated risk for suicidal thoughts and behaviors.

In a study published in JAMA last year, Dr. Brent and other researchers concluded that the benefits of treatment with the drugs outweighed the risks.

Other co-authors of the study published today include researchers from the University of Texas Southwestern Medical Center at Dallas; University of California, Los Angeles; University of Texas Medical Branch, Galveston; Brown University; Kaiser Permanente Center for Health Research, Portland, Ore.; National Institute of Mental Health.