The largest clinical trial studying the use of antidepressants for treating major depression in adolescents suggests that paroxetine, sold under the brand name Paxil, may be successful.
"This is the first substantial evidence of a safe and effective treatment with an antidepressant for adolescents," said Martin B. Keller, M.D., who led the study, which appears in the July issue of the Journal of the Academy of Child and Adolescent Psychiatry.
The Food and Drug Administration does not currently approve any antidepressant for use in teens. At least two large-scale studies involving drug safety, efficacy, metabolism and action are necessary for such a classification. "This one study provides such evidence," Keller said.
In the study, researchers examined two different classes of antidepressants that work in adults. This was the first large-scale, double-blind, placebo-controlled comparison of paroxetine, a selective serotonin reuptake inhibitor (SSRI), and imipramine, a tricyclic antidepressant, to treat teens with major depression. GlaxoSmithKline, makers of Paxil, funded the research.
The study involved 275 patients at 12 psychiatric centers. Across several outcome measures, paroxetine lessened depression symptoms and improved patient moods better than imipramine or placebo. In the primary rating scale for depression, paroxetine produced a 63-percent response rate compared to 50 percent for imipramine and 46 percent for placebo.
The acute phase of the trial lasted eight weeks, with a final average daily dose of 28 mg of paroxetine.
"Our hope is that this study provides clinicians and families with an understanding of what can be done for a depressed adolescent in terms of an effective treatment," said Keller, who is professor and chairman of the Department of Psychiatry and Human Behavior in the Brown Medical School.
About 15 percent of teens suffer from major depression, characterized by frequent and protracted bouts of depression and considerable social and academic impairments. Suicide, strongly linked to major depression, is the second leading cause of death among teens.
Prior to this study, there had been few tightly controlled, large-scale randomized trials of antidepressants in teens. Most basic questions about how to treat this age group were left unanswered.
This study was two-and-a-half times larger than any previous antidepressant clinical trial in teens. The paroxetine was generally well tolerated by patients. Statistically significant side effects included headache, nausea, dizziness, dry mouth and sleepiness. One of the study's limitations is that 37 percent of patients failed to respond to the paroxetine, which is a typical non-responder rate in SSRI trials, Keller said.
In the study, the overall response for imipramine did not differ appreciably from placebo for any measure. No study has found that a tricyclic compound, including imipramine, successfully treats adolescent depression. In fact, tricyclic compounds have been linked to adverse health effects, including a major risk of overdose, in adolescent studies. During the study, almost one-third of patients stopped imipramine therapy because of adverse effects.
Researchers at Brown and five other sites nationwide are recruiting adolescents for a study of how to care for patients with major depression for whom initial treatment with five of the most commonly prescribed SSRIs does not entirely work.
The National Institute of Mental Health is funding the five-year study of 400 teens. Researchers are recruiting adolescents between the ages of 12 and 18, who are currently in treatment for depression. Individuals must be taking an SSRI for at least six weeks with little or no improvement. Researchers will try variations of antidepressants and cognitive behavior therapy with the subjects.
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