The FDA issued Prozac (fluoxetine) a "black box" waring in the Fall of 2004 after findings showed an increased risk of suicidal thoughts and behaviors in some children and adolescents taking the drug.
University of Texas at Austin doctoral student Kereshmeh Taravosh-Lahn, who led the study, tells Science Daily, "It is unwise to expect a drug to work the same in juveniles as in adults."
The researchers injected both the juvenile and adult hamsters with high or low doses of Prozac. They found that the juvenile hamsters injected with a low dose of the drug became extremely aggressive, while a high dose seemed to inhibit aggression to a degree. Adult hamsters were calm on both high and low doses.
Taravosh-Lahn says the study adds to growing evidence that the brain is still maturing during puberty and "could possibly react to drugs given to adults in different and potentially negative ways."
"We need to understand how these drugs will affect the developing nervous system before giving them to children," he says.
The researchers say the discrepancy in the drug's effects may be due to varying levels of the neurotransmitter serotonin. They say children may respond differently because there is not enough serotonin in their systems for Prozac to work properly.
Dr. Jon Shaw, director of child and adolescent psychiatry at the University of Miami Miller School of medicine, noted that the study has limitations, however.
Shaw tells HealthDay News, "Just remember that a hamster is a hamster is a hamster."
He says, "There are a lot of studies on the maturation and evolution of the central nervous system structure through adolescence, and nobody thinks the adult brain is [the same as] the child's brain. And this just reminds us that other studies are needed to try and understand what the difference means in terms of metabolism of drugs."
