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Psychology Professor Receives Funding to Study Drug Use

Krista Lisdahl Medina has researched extensively on the neurocognitive effects of marijuana use in adolescents. Now she is taking on a new subject: Ecstasy.

Date: 9/15/2009
By: Kim Burdett
Phone: (513) 556-8577
Krista Lisdahl Medina is a clinical neuropsychology researcher in University of Cincinnati’s Department of Psychology. She is also the director of UC’s Brain Imaging and Neuropsychology (BraIN) Laboratory, which looks at neurocognitive consequences of drug and alcohol use, among other things.

Medina was recently awarded a $471,000 grant by the National Institute on Drug Abuse for her proposal, “Effects of SLC6A4, BDNF and Ecstasy Use on Brain Structure in Young Adults.”

You’ve long been interested in the effects of drugs and alcohol on the brain. Why is that?

Krista Medina.
'Here at UC, our survey found that 7 percent of students had used Ecstasy,' Medina says. She plans to use MRI images to observe the effects Ecstasy has on the brain.

I have been curious about the effects of drugs on the brain since college, when I got introduced to psychopharmacology and cognitive neuroscience courses. I often wondered how chronic use of drugs changed brain structure and function over time. I am interested in these questions so we can understand the brain better (for example: what happens when you manipulate the endogenous cannabinoid or serotonin system with drugs over time?) and, ultimately, help improve prevention campaigns and drug and alcohol treatment.

You recently presented your findings about marijuana use among adolescents. What was the most interesting component of that research?

From my collaborative work with Dr. Susan Tapert (University of California, San Diego), we have found that marijuana use is associated with poorer cognitive functioning—especially psychomotor speed and complex attention—even after one month of abstinence. Further, adolescents have larger volumes in brain regions such as the left hippocampus, prefrontal cortex (only in girls), and part of the cerebellum. Larger brain volumes were associated, in general, with poorer cognitive function. Thus, it is possible that chronic marijuana use during adolescence may interrupt the healthy pruning process—although this needs to be confirmed in animal models.

This grant by the National Institute on Drug Abuse looks at Ecstasy use and its effects on cognitive function. What made you decide to study ecstasy?

Ecstasy (MDMA) use continues to be major public health problem, especially among young adults. Here at UC, our survey found that 7 percent of students had used Ecstasy. My previous research demonstrated significant verbal memory impairment in abstinent recreational ecstasy users. In fact, just using two tablets a month on average was associated with impaired verbal memory in young adults, which is alarming! Still, we still do not know exactly what happens to the brain structure after repeated Ecstasy use in young adults and adolescents.  

How is Ecstasy the same and/or different from the other drugs you’ve studied?

Ecstasy has both stimulant and hallucinogen properties and affects the brain by binding to the serotonin transporter in the brain. Unlike marijuana, alcohol and nicotine users, Ecstasy users tend to be recreational users and do not use daily—or even weekly. They tend to be heavy polydrug users—oftentimes using marijuana frequently (daily or weekly) and recreationally using Ecstasy along with other stimulants (cocaine, methamphetamine) and hallucinogens (LSD, mushrooms, salvia). So, Ecstasy can be complicated to study; you have to control for the polydrug use to examine which effects are specifically due to Ecstasy. We are also interested in examining whether simultaneous use of Ecstasy plus alcohol or marijuana results in poorer thinking abilities.

What are you trying to find and how will you go about finding it?

This project will increase our understanding of the links between genetic variations that affect serotonin signaling, Ecstasy consumption, and brain function in young adults. I will be recruiting three groups of young adults: controls (no drug use), marijuana users (no Ecstasy use) and Ecstasy users. All study participants will complete neuropsychological testing (measuring memory, executive functioning, motor speed) and undergo a brain scan (magnetic resonance imaging). We will also collect a DNA sample from everyone. We will then be able to see if Ecstasy use is associated with abnormal thinking or brain structure and if an individual’s genetics places them at increased risk for such abnormalities.  

What are the overall implications of such research?

The data will be critical for explaining individual differences in susceptibility for Ecstasy-induced thinking problems and brain structure abnormalities. Specifically, this study will determine whether combined serotonin transporter (SLC6A4) and brain-derived neurotrophic factor (BDNF) polymorphisms significantly explain individual differences seen in long-term effects of Ecstasy usage.

Ultimately, we hope that information gained from this study will help advance genetically targeted, biologically based treatments aimed at improving neurocognitive functioning and reducing drug use in young adults. More globally, the study results will help advance the understanding of individual differences in susceptibility to the numerous serotonin-related disorders like drug use and depression.

Read more about Medina’s research: 
Research Finds That Marijuana Use Takes Toll on Adolescent Brain Function

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