"Depression is a devastating illness that is often accompanied in females by an inability to concentrate and learn," said Tracey J. Shors, an associate professor in the department of psychology. "Our data show that while Prozac is an effective drug for treating depression, it also protects females from the adverse effects of stress on learning."
Shors will present her findings in a paper, "Serontinergic Antidepressants Protect Females from the Adverse Effects of Stressful Experience on Learning," at the Society for Neuroscience annual meeting in Orlando, Fla., Nov. 1-6.
Shors and her research team, Benedetta Leuner, Jacqueline Falduto and Sabrina Mendolia, studied adult female rats treated with the antidepressant Prozac and a control group that received no treatment. They found that after a stressful event, learning was impaired in the control group but not in the group treated with Prozac. The researchers also found that only chronic treatment with Prozac was effective, which is consistent with reported efficacy of Prozac in patients with depression and other mental disorders.
"Importantly," Shors pointed out, "unstressed females treated with Prozac did not differ from unstressed, untreated females, indicating that Prozac itself did not affect learning."
Shors noted that males and females differ in their responses to stressful experiences. The researchers have found that exposure to a stressful experience that impairs new learning in females actually enhances new learning in males.
Since twice as many women experience depression and other stress-related mental illnesses as men, these data underscore the need to include females in research aimed at understanding the biology of mental illness, Shors said.
"It would be interesting to know whether Prozac affects learning in males after they have experienced a stressful event," she added.
Shors hopes to do more research to find out just how Prozac works in the brain. In other research, her team found that stressful experience alters the anatomy of neurons in the hippocampus, a brain region necessary for memory formation. Specifically, they found that exposure to stressful experience increases the presence of neuronal connections in the male hippocampus but reduces their presence in the female hippocampus. "We plan to investigate whether long-term treatment with Prozac also protects the female brain from other adverse effects of stressful experience, " Shors said.