By Karla Harby

      BOSTON, May 15 (Reuters Health) - Ritalin and Prozac, as well as various combinations of similar stimulants and antidepressants, are being prescribed together for an increasing number of children, according to a new study presented here.

      Among those children taking Prozac, Zoloft, Luvox or Paxil--collectively known as selective serotonin reuptake inhibitors (SSRIs) and prescribed for depression, school phobias, bed wetting and eating disorders--in 1998, 30% were also taking Ritalin, dexedrine or related drugs, presumably for attention-deficit disorder.

      When the researchers considered those children on Ritalin or similar drugs, they found that 8% were also taking an SSRI.

      "I think the safety of these medications--in the young child especially--is not known, and when you take them in combination it's a whole new level of safety concern," noted Dr. Jerry Rushton of the University of Michigan in Ann Arbor. "It's something that needs to be studied further."

      These findings are in addition to the overall trends showing a steep increase in the number of children taking either drug type from 1990 through 1998, Rushton pointed out. By 1998, 10% of children aged 6 to 14 years were on Ritalin or stimulants, as were 1% of preschoolers aged 1 to 5 years. For SSRIs like Prozac, 2% of school-age children and 0.1% of preschoolers had prescriptions for the drugs.

      These drugs are relatively new, and some increase in use over time would be expected, but the dual prescriptions are surprising, Rushton added.

      Rushton also found that by 1998, just as many girls as boys were taking SSRIs. When these drugs were first introduced, girls were given antidepressant prescriptions twice as often as boys. The gender gap for Ritalin likewise has narrowed, with three times as many boys as girls on the drug in 1998, compared with the 10 to 1 ratio of the 1980s.

      The reasons for these findings are unknown. "The trends could be due to an increase in recognition and diagnosis, and that's maybe a very positive thing--we're treating children who were missed in the past," Rushton speculated.

      But he said the other hypothesis is that the trends show over-diagnosis, the idea that "if the child is not doing so well, then if one drug didn't work, maybe we should try two or three."

      Rushton based his study on North Carolina Medicaid data for prescription claims. He presented his findings at the combined annual meeting of the Pediatric Academic Societies and the American Academy of Pediatrics.