Effect of antidepressant warnings moderate-US study

CHICAGO (Reuters) - Warnings that antidepressants might increase the risk of suicidal behavior in youth curbed rapid growth of these drugs but did not eliminate access to them among young people as some had feared, U.S. researchers said Monday.

They said that while antidepressants had been growing at an annualized rate of 36 percent before regulators made the warnings in 2003, that growth flattened out after the warnings were issued.

Doctors have assumed that a spike in teen suicide in 2004 reulted from a sharp fall in use of antidepressants among children and youth.

That was not the case, according to Dr. Mark Olfson of Columbia University Medical Center.

"When the warnings first appeared, there was a great deal of concern among psychiatrists and other mental health professionals that these warnings would result in a precipitous decline in antidepressant use by young people, and as a result, youth with depression would have less access to treatment," said Olfson, whose study appears in the Archives of General Psychiatry.

"What we found is the FDA warnings had a relatively moderate and targeted effect in slowing the growth of antidepressant use by children," Olfson said in a telephone interview.

Recent studies have suggested the drug warnings triggered an 8 percent rise in suicide among youth and teens in 2004, the biggest one-year gain in 15 years.

U.S. and European regulators sent out a series of public health warnings on use of the drugs beginning in 2003 after clinical trials showed the drugs increased the risk of suicidal thoughts and behaviors in children and teens.

In 2004, the U.S. Food and Drug Administration issued its strongest warning, a so-called "black box," on the use of all antidepressants in children and teens to draw attention to the possible risks of these medications.

Olfson and colleagues wanted to see the overall impact of the public health warnings and of the FDA's black box warning.

MONITORING SUICIDE RATES

They reviewed U.S. prescription data from before a June 2003 warning by FDA to monitor adolescents taking GlaxoSmithKline's antidepressant Paxil, known generically as paroxetine hydrochloride, for signs of worsening depression and suicidal thoughts.

The researchers also studied antidepressant use in the period leading up to the strict black box warning on all antidepressants, and the period 15 months after the warnings.

They found that prior to the public health warnings, antidepressant use in youth -- those aged 6 to 17 -- had been rising at an annualized rate of 36 percent. But use of these drugs in this age group flattened after the initial warnings in 2003 and that rate did not change significantly after the black box warning was issued in late 2004.

Olfson said the changes in antidepressant use have been confined to youth and young adults, and that adults continued to take the drugs.

The American Foundation for Suicide Prevention said the FDA black box warnings and the drop in antidepressant prescriptions were the most likely cause of the higher suicide rates in young people in 2004.

But Olfson said preliminary figures suggest teen suicide rates in 2005 actually declined from 2004. "This suggests that we need to look more carefully at this issue," he said.

Olfson said his study should address some concerns among physicians that the black box warning went too far.

"There are still a number of physicians who feel the FDA overshot and that these warnings had a dramatic chilling effect," Olfson said.

"I think this study will provide evidence that ... it was not as profound as some physicians have imagined," he added.

The FDA has said it will continue to monitor suicide rates in youth and teens to see if rates continue to rise.

Depression is the leading cause of suicide, which is the third-biggest killer of children and young adults between the ages of 10 and 24.

(Editing by Will Dunham and Cynthia Osterman)