Some 10 percent of children visiting pediatric hospitals as outpatients are suffering psychological problems, mostly girls aged 15 and boys aged 14, according to the results of the first nationwide survey on children's mental health.

The girls outnumber the boys, it showed.

The survey, carried out by a group of experts, including Zentaro Yamagata, a professor of health education at Yamanashi Medical College, was released in a meeting of the Japan Epidemiological Association in late January.

Yamagata is a member of a task force at the Health, Labor and Welfare Ministry studying psychosomatic problems and neurosis.

About 10,000 children are said to be visiting medical institutions, including clinics, each day as outpatients for emotional problems. "Pediatricians must know how to deal with mental problems," Yamagata said.

Despite the increase in children suffering from psychosomatic disorders, no detailed nationwide survey on the trend has been conducted. The disorders are believed to be the cause of the growing "classroom collapse" phenomenon, where class discipline breaks down to the point where teaching becomes impossible.

Yamagata and other experts asked medical research facilities across the nation recognized by the Japan Pediatric Society to survey children visiting these facilities as outpatients on Oct. 18, 1999, and received replies from 454, or 80 percent, of them.

The group analyzed reports on about 16,300 children surveyed and said that the number diagnosed as having psychological problems began to rise in elementary school. Mental suffering tends to peak at age 14 for boys, and at 15 for girls. The numbers begin to decrease once they enter high school.

The number of girls with mental problems in higher grades of elementary school outnumbers that for boys, with one in four 15-year-old girls visiting pediatricians as outpatients found to have had mental problems.

In another survey, Yamagata and other experts found that students in their third year of junior high visit nurse's offices for mental distress in increasing numbers. Adolescence and stress before high school entrance examinations are commonly cited factors.

Children with psychological problems complain of sluggishness, headaches, stomachaches, nausea and diarrhea, two to five times more than those without mental problems, the experts said.

"A considerable number of children are troubled by mental problems. A system for pediatricians to take care of those with such problems should be created," Yamagata said.