Around half of US teens meet the criteria for a mental disorder and nearly one in four report having a mood, behavior or anxiety disorder that interferes with daily life, American researchers say.
Fifty-one percent of boys and 49 percent of girls aged 13-19 have a mood, behavior, anxiety or substance use disorder, according to the study published in the Journal of the American Academy of Child and Adolescent Psychiatry.
In 22.2 percent of teens, the disorder was so severe it impaired their daily activities and caused great distress, says the study led by Kathleen Merikangas of the National Institutes of Mental Health (NIMH).
"The prevalence of severe emotional and behavior disorders is even higher than the most frequent major physical conditions in adolescence, including asthma or diabetes," the study says.
Mental problems do not get the same attention from public health authorities even though they cost US families around a quarter of a trillion dollars a year, according to the study.
Around nine percent of all US children have asthma and less than a quarter of one percent of all people under the age of 20 have diabetes, according to the Centers for Disease Control and Prevention (CDC).
Merikangas and a team of researchers analyzed data from the National Comorbidity Study-Adolescent Supplement, which surveyed more than 10,000 US teens.
The study is the first to track the prevalence of a broad range of mental disorders in a nationally representative sample of US teens.
They found that nearly a third of the teens met the criteria for the most common mental disorder among US youth, anxiety disorders, which include social phobia and panic "attacks".
This class of disorder also had the earliest median onset age, occurring in children as young as six years old.
Behavior disorders, including attention deficit hyperactivity disorder, were the next most common condition (19.1 percent), followed by mood disorders (14.3 percent) such as depression.
Eleven percent of teens with a mood disorder, 10 percent with behavior disorders and eight percent who had anxiety disorders, especially social phobics, met the criteria for severe impairment, meaning their condition affected their day-to-day life and caused them great distress.
Teen mental disorder rates mirror those seen in adults, suggesting that most adults develop a mental disorder before adulthood, say the researchers, calling for earlier intervention and prevention, and more research to determine what the risk factors are for mental disorders in youth.