Washington, D.C. ? New government figures show a surprising increase in youth suicides after a decade of decline, and some mental health experts think a drop in use of antidepressant drugs may be to blame.

The suicide rate climbed 18 percent from 2003 to 2004 for Americans under age 20, from 1,737 deaths to 1,985. Most suicides occurred in older teens, according to the data – the most current to date from the federal Centers for Disease Control and Prevention.

By contrast, the suicide rate among 15- to 19-year-olds fell in previous years, from about 11 per 100,000 in 1990 to 7.3 per 100,000 in 2003.

Suicides were the only cause of death that increased for children through age 19 from 2003-04, according to a CDC report released Monday.

Antidepressant use among children decreased during the same time period.

“This is very disturbing news,” said Dr. David Fassler, a University of Vermont psychiatry professor.

He noted that the increase coincided with regulatory action by the U.S. Food and Drug Administration that led to a black box warning on prescription packages cautioning that antidepressants could cause suicidal behavior in children.