McLean Study Identifies New Area of Brain Linked to Drug Addiction

October 11, 2005

Cynthia Lepore
Public Affairs

Belmont, MA - Researchers at Harvard-affiliated McLean Hospital say they have identified an area of the brain that appears to play a key role in why cocaine and other stimulants are so highly addictive, a finding that could ultimately lead to new targeted treatments for addiction and other brain disorders.

"We found the region of the brain known as the cerebellar vermis, which is also involved in other psychiatric illnesses, appears to play a role in drug addiction," said lead researcher Carl Anderson, PhD, of McLean Hospital's Brain Imaging Center. The research appears in the Oct. 12 issue (PubMed) of the journal Neuropsychopharmacology.

"Scientists previously contended that the vermis had little involvement in addiction or other disorders involving dopamine. This changes the perspective on how brain regions may interact during addiction. It introduces an entirely new player," Anderson added. The study involved the review of previously published data on the vermis that had not been analyzed for its involvement in addiction. The vermis, a worm-shaped brain area located in the cerebellum near the back of the head, affects people's ability to concentrate.

In the original study conducted in 1998 by Luis Maas, MD, PhD, one of the authors of the new report, researchers used magnetic resonance imaging (MRI) to scan the brains of 10 crack-cocaine abusers as they viewed a video of people lighting up a crack pipe. When compared to a control group of non-users, the study found that the users-and not the comparison subjects-both reported an increased desire for cocaine following this cue and had increased activity in several brain areas, including the anterior cingulate cortex.

The new analysis conducted by McLean's Anderson and colleagues shows activation in the vermis in cocaine users while they viewed the cocaine-use video. "The vermis appears more responsive to cocaine cues in people who abuse cocaine," said co-author Marc J. Kaufman, PhD.

As part of the investigation, Anderson also reanalyzed data from an unrelated study collected by Alan J. Fischman, MD, in collaboration with Bertha Madras, PhD, two authors of the new study. Their earlier analysis showed the distribution of a drug that targets the dopamine transporter, the protein that seems to be blocked by such stimulants as cocaine, through the use of positron emission tomography (PET). The new data show, in non-drug using subjects, that the vermis may contain dopamine transporters and thus may be a target for cocaine and other stimulants, thereby increasing dopamine in the brain.

If the vermis plays a key role in the brain's dopamine system, as the new McLean Hospital findings suggest, this could explain its role in addiction, as well as in other brain disorders, such as Parkinson's disease, which is characterized by a shortage of dopamine, and ADHD.

The new findings "seem to support the conclusion that the vermis is a brain area involved in stimulant response," Anderson said. "If this finding holds true, it could help change our understanding of addiction."

"One possibility is that the vermis acts as an "Achilles Heel" in sensitive individuals," he noted. "This information could ultimately help us to develop addiction treatments by targeting the vermis therapeutically."

McLean Hospital, consistently ranked the nation's top psychiatric hospital by U.S. News & World Report, is an affiliate of Harvard Medical School and Massachusetts General Hospital and a member of Partners HealthCare.

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