Mega Doctor News
By University of Texas at El Paso
EL PASO, Texas – As scientists seek to understand the long-term effects of antidepressants given to teens, a new study from The University of Texas at El Paso finds that the use of antidepressants, particularly Prozac, in adolescent women may contribute to increased pain sensitivity later in life.
“Our collective body of research on this topic is starting to uncover a complex picture, where adolescent Prozac exposure can shape the brain in lasting ways,” said UTEP’s Sergio Iñiguez, Ph.D., the principal investigator behind the new study on mice that’s published in the Journal of Psychiatric Research.
Iñiguez, a professor of psychology who studies anxiety and depression, said that research is increasingly finding that drugs like Prozac may have lasting effects beyond mood regulation.
Antidepressant dispensing rates, Iñiguez said, have been on the rise for years and increased significantly after the pandemic, particularly for young girls. A study cited by Iñiguez found that antidepressant dispensing to young adults was rising before the outbreak of the COVID-19 pandemic and rose 63.5% faster afterwards, particularly for female patients.
Antidepressants include drugs like Prozac, also known as fluoxetine, a category of medicine known as a selective serotonin reuptake inhibitor (SSRI) that is widely used to treat depression, anxiety, obsessive compulsive disorder and other mood disorders. While these drugs are safe for use in adolescents, not enough is known about their long-term effects, Iñiguez said.
The UTEP research team set out to design a study that tests pain sensitivity in adult, female mice who had received Prozac as adolescents. Mice are commonly used in psychological research because their genetic similarity to people means that their responses will generally approximate human responses, the team explained.
Anapaula Themann, a doctoral student in psychology and the lead author of the study, explained that 20 adolescent female mice were given water with Prozac mixed in for two weeks. When they became adult mice at approximately 70 days of age — weeks after the treatment ended — their pain sensitivity was tested by placing them on a hot plate. The hot plate was warm enough to cause some discomfort over time but not hot enough to cause real pain.
Each mouse was placed on the hot plate for 30 seconds or until they licked their back paws. Much like dogs, mice lick their paws as a way to manage discomfort, Themann said. She explained that compared to a control group, the mice who had received the Prozac as adolescents were much faster to lick their paws, indicating increased sensitivity. Researchers also observed that the mice who received Prozac had a lower body weight than those in the control group who had never received it.
Themann and Iñiguez theorize that Prozac use in adolescents can disrupt the maturation of the medial prefrontal cortex, a brain region that assists with pain regulation. The drug may also increase inflammatory markers within the brain that contribute to nociception, the process of identifying harmful stimuli and creating the sensation of pain.
Future studies will focus on the biology behind the increased sensitivity to pain within the mice’s brains.
Themann said, “Now that we know that juvenile Prozac exposure increases pain sensitivity in adulthood, we plan to investigate the brain-mechanisms responsible for this long-term side effect.”
Iñiguez and Themann emphasized that antidepressants often provide necessary mental health support.
“Treatments like Prozac can be an incredibly useful tool for addressing illnesses like depression and anxiety,” Iñiguez said. “Learning more about their long-term effects can help us understand the full picture and ultimately improve the medications and treatment protocols.”
The research was funded by the National Institute for General Medical Sciences, part of the National Institutes of Health.
About The University of Texas at El Paso
The University of Texas at El Paso is America’s leading Hispanic-serving university. Located at the westernmost tip of Texas, where three states and two countries converge along the Rio Grande, 84% of our 25,000 students are Hispanic, and more than half are the first in their families to go to college. UTEP offers 171 bachelor’s, master’s and doctoral degree programs at the only open-access, top-tier research university in America.
