Title:Combined Chronic Oral Methylphenidate and Fluoxetine Treatment
During Adolescence: Effects on Behavior
Volume: 24
Issue: 10
Author(s): Panayotis K. Thanos*, Madison McCarthy, Daniela Senior, Samantha Watts, Carly Connor, Nikki Hammond, Kenneth Blum*, Michael Hadjiargyrou, David Komatsu and Heinz Steiner
Affiliation:
- Behavioral Neuropharmacology and Neuroimaging Laboratory (BNNL), Clinical Research Institute on Addictions,
Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo,
Buffalo, NY 14051, USA
- Department of Psychology, University at Buffalo, Buffalo, NY, 14203, USA
- College of
Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
Keywords:
reward deficiency syndrome, dopamine, serotonin, ADHD, drug abuse.
Abstract:
Background: Attention Deficit Hyperactivity Disorder (ADHD) can be comorbid with
depression, often leading to the prescription of both methylphenidate (MP) and selective serotonin
reuptake inhibitor (SSRI) antidepressants, such as fluoxetine (FLX). Moreover, these drugs are often
misused as cognitive enhancers. This study examined the effects of chronic oral co-administration of
MP and FLX on depressive- and anxiety-like behaviors.
Methods: Adolescent rats received daily either water (control), MP, FLX, or the combination of MP
plus FLX in their drinking water over the course of 4 weeks.
Results: Data analysis shows a decrease in food consumption and body weight for rats exposed to
FLX or the combination of MP and FLX. Sucrose consumption was significantly greater in FLX or
MP+FLX groups compared to controls. FLX-treated rats showed no effect in the elevated plus maze
(EPM; open arm time) and forced swim test (FST; latency to immobility). However, rats treated with
the combination (MP+FLX) showed significant anxiolytic-like and anti-depressive-like behaviors (as
measured by EPM and FST), as well as significant increases in overall activity (distance traveled in
open field test). Finally, the combined MP+FLX treatment induced a decrease in anxiety and depressive-
like behaviors significantly greater than the response from either of these drugs alone.
Conclusion: These behavioral results characterize the long-term effects of these drugs (orally administered)
that are widely co-administered and co-misused and provide important insight into the potential
neurobiological and neurochemical effects. Future research will determine the potential risks of
the long-term use of MP and FLX together.
