Study To Examine Marijuana’s Impact on the Brain

By Paul Gaita 12/30/14

Indiana University researchers will examine the drug's effect on the brain over time.


Researchers at Indiana University are conducting a study to determine exactly how marijuana affects the structure and function of the brain. Magnetic resonance imaging (MRI) is being employed to analyze 90 participants, all ages 18 to 35, comprised of current and former pot users, as well as those who have never used marijuana.

Participants will be asked to undergo tests of perception, memory and thinking, and report any issues they may be experiencing as a result of their pot use. The research team will then conduct connectivity analysis on the data culled from all three groups to determine the efficiency of communication between the brain regions. “I like to think of the brain as an electrical circuit,” said study co-leader Sharlene Newman, an associate professor at Indiana University and head of the school’s Brain Imaging Facility.

“If the insulation on the wires is not intact, you can get current leakage resulting in faulty communication," Newman added. "If the connections between brain regions are faulty, then the functioning of the brain will be faulty or inconsistent. With the MRI techniques we will use, we will be able to examine the integrity of the insulation.”

A host of studies conducted by other researchers have uncovered connections between marijuana use and altered moods, perception, coordination, problem-solving and brain development, though these have been inconsistent in terms of providing solid results, as Dr. Francesca Filbey, associate professor in the School of Behavioral and Brain Sciences at the University of Texas at Dallas, has noted. Some studies have also suggested a link between marijuana use in adolescents and incidents of schizophrenia, though again, no conclusive evidence links the two scenarios.

Newman and study co-lead Brian O’Donnell have authored previous studies that have concluded that cannabis alters connectivity in the brain, making it operate in a less efficient manner. The new study hopes to determine whether brain function recovers after individuals stop using the drug for an extended period of time.

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Paul Gaita lives in Los Angeles. He has contributed to the Los Angeles Times, Variety, LA Weekly, and The Los Angeles Beat, among many other publications and websites.