June 20, 2005
PET Confirms Changes at Brain Molecular Level in Bulimia Nervosa Patients after CB Therapy
TORONTO, Canada--Positron emission tomography (PET) imaging has detected brain molecular changes in patients who have undergone cognitive behavioral therapy for bulimia nervosa, notes a study released at the Society of Nuclear Medicine's 52nd Annual Meeting June 18"“22 in Toronto.
"This is the first study to examine opioid receptors in bulimia nervosa, and research showed that treatment caused a change in the opioid binding in patients," said Angela S. Guarda, M.D., assistant professor with the department of psychiatry and director of the Eating Disorders Program at Johns Hopkins University School of Medicine, Baltimore, Md. PET scans showed that cognitive behavior therapy affected the brain's natural system of chemicals called opioids, which are known to play a role in quelling painful sensations, heightening positive emotions and creating a sense of reward. "Our results demonstrate a relationship between mu-opioid receptor binding in brain regions underlying feeding and reward in bulimia nervosa," added the co-author of "Brain Mu-Opioid Receptor Binding Measured by [11-C]-Carfentanil Positron Emission Tomography (PET) Demonstrates Changes in Bulimia Nervosa (BN) Following 12 Sessions of Cognitive Behavioral Therapy (CBT)."The first imaging study to implicate the opioid system in bulimia nervosa "shows differences in the brain's opioid system in women with bulimia compared to healthy women in three brain areas known to play a role in substance abuse," said Guarda. "Treatment with cognitive behavioral therapy alters these differences. Our results suggest that involvement of the opioid system may explain the addictive quality of this behavioral disorder," she added. "These findings also suggest that PET imaging could potentially play a role in optimizing treatment for bulimia based on brain chemistry," detailed Guarda. PET is a powerful medical imaging modality that noninvasively uses special imaging systems and radioactive tracers to produce pictures of the function and metabolism of the cells in the body. PET scans are performed with an imaging radiopharmaceutical--most commonly FDG (fluorodeoxyglucose)--that can be imaged by a PET scanner, providing a picture of a patient's individual physiology.
This study, which examined patients before and after 12 sessions of cognitive behavioral therapy, "shows that higher opioid binding before treatment in a region of the brain called the insula predicted better response," said Guarda. PET scans in the future may be able to help "match patients to treatment," said Guarda. For example some patients are known to respond to low-intensity treatment and self-help interventions; others require intensive treatment on an inpatient behavioral eating disorders unit. Results suggest that medications used in treating addiction may be helpful in treating bulimia, she noted.
"This research finding shows an interesting--and potentially powerful--use of PET, illustrating that behavioral therapy may affect bulimia at the brain-chemical level," said Peter Herscovitch, M.D., a vice chair of SNM's Scientific Program Committee (Neurosciences Track), chief of the PET imaging section at the National Institutes of Health (NIH) in Bethesda, Md., and senior staff physician at the NIH Clinical Center.
Bulimia nervosa is a serious eating disorder marked by a destructive pattern of binge eating and recurrent inappropriate behavior to control one's weight, explained Guarda. It is a driven behavioral disorder where individuals are stuck in a cycle of binging and purging, similar to drug addiction, she said. Bulimia nervosa, which is 10 times more common in females than in males, affects 1"“2 percent of adolescent girls and young women in the United States. Bulimia may become chronic and lead to serious health problems, including seizures, irregular heartbeat, dental erosion, swollen salivary glands, thin bones, gastrointestinal irritation and electrolyte imbalances (especially of potassium, calcium, sodium and chloride). In rare cases, it may be fatal. While the cause of bulimia nervosa is still unknown, research shows that certain brain chemicals may function abnormally in bulimia patients. Cognitive-behavioral therapy, which teaches patients how to change abnormal thoughts and behavior, is one form of treatment for bulimia nervosa.
The authors of "Brain Mu-Opioid Receptors Binding Measured by [11c]-Carfentanil Positron Emission Tomography (PET) Demonstrates Changes in Bulimia Nervosa (BN) Following 10 Weeks of Cognitive Behavioral Therapy (CBT)" are Ismail Alhamrawy, department of radiology, Johns Hopkins University School of Medicine, Baltimore, Md.; Angela Guarda and Janelle Coughlin, department of psychiatry, Johns Hopkins University School of Medicine, Baltimore, Md.; Badreddine Bencherif, department of radiology, University of Pittsburgh, Pittsburgh, Pa.; Badreddine Bencherif, department of radiology, University of Pittsburgh, Pittsburgh, Pa.; Robert Dannals, department of radiology, Johns Hopkins University School of Medicine, Baltimore, Md.; and James Frost, departments of radiology and radiological sciences, Johns Hopkins University School of Medicine, Baltimore, Md.
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