Nearly three million adolescents are struggling with depression and most never get the help they need because of prejudice about mental illness, inadequate mental-health resources and widespread ignorance about how emotional problems can wreck young lives, Newsweek reports in its October 7 cover story (on newsstands Monday, September 30). And while no one knows whether there are actually more depressed kids today or just greater awareness of the problem, some researchers think that the stress of a high divorce rate, rising academic expectations and social pressure may be pushing more kids over the edge.

Scientists say that early onset of depression in children and teenagers has become increasingly common, with some even using the world "epidemic," report Washington Correspondent Patricia Wingert and Senior Editor Barbara Kantrowitz. Suicide is now the third leading cause of death among 10- to 24-year-olds, and the National Institutes of Mental Health (NIMH) estimates that 8 percent of adolescents and about 2 percent of children (some as young as 4) have symptoms of depression.

This marks a significant change from a decade ago, when many doctors considered depression strictly an adult disease. Teenage irritability and rebelliousness was "just a phase" kids would outgrow. But scientists now believe if this behavior is chronic it often signals serious problems, and new brain research is also beginning to explain why teenagers may be particularly vulnerable to mood disorders. Both anti-depressant medications and talk therapy have enabled many teenagers to regain their footing. And more effective treatment may be available in the next few years, Newsweek reports.

Often the trigger for adolescent depression is not obvious. Scientists are studying a combination of factors, both internal and external. The hormonal surges of puberty have long been shown to affect moods, but now new research says that changes in brain structure may also play a role. And they believe there is also a genetic predisposition to depression.

On college campuses, meanwhile, experts say cases of depression are too often misdiagnosed as mononucleosis or chronic fatigue syndrome. That's why many kids still suffer unnoticed, even though more schools are using effective screening tools to identify kids who should be referred for a professional evaluation.