Anorexia Linked to Notable Shrinkage of Key Brain Structures

Megan Brooks

June 24, 2022

Patients with anorexia nervosa (AN) have notable shrinkage in key brain structures and these deficits are less severe in patients on the path to weight recovery, a new brain imaging study shows.

The reductions of cortical thickness, subcortical volumes, and cortical surface area were "very pronounced in acutely underweight anorexia," Stefan Ehrlich, MD, PhD, head of the Eating Disorder Treatment and Research Center, Technical University in Dresden, Germany, told Medscape Medical News.

Yet even a "partial weight gain brings some normalization of these shrinkages. From this it can be deduced that a fast/early normalization of weight is also very important for brain health," said Ehrlich.

The study was published online May 31 in Biological Psychiatry.

"A Wake-Up Call"

Researchers with the international ENIGMA Eating Disorders Working Group analyzed T1-weighted structural magnetic resonance imaging (MRI) scans for nearly 2000 people with AN (including those in recovery) and healthy controls across 22 sites worldwide.

In the AN sample, reductions in cortical thickness, subcortical volumes, and, to a lesser extent, cortical surface area, were "sizable (Cohen’s d up to 0.95), widespread, and co-localized with hub regions," they report.

These reductions were two and four times larger than the abnormalities in brain size and shape seen in patients with other mental illnesses, the researchers note.

Noting the harmful impact of anorexia-related undernutrition on the brain, these deficits were associated with lower body mass index (BMI) in the AN sample and were less severe in partially weight-restored patients — implying that, with appropriate early treatment and support, the brain might be able to repair itself, the investigators note.

"This really is a wake-up call, showing the need for early interventions for people with eating disorders," Paul Thompson, PhD, author and lead scientist for the ENIGMA Consortium, said in a news release.

"The international scale of this work is extraordinary. Scientists from 22 centers worldwide pooled their brain scans to create the most detailed picture to date of how anorexia affects the brain," Thompson added.

"The brain changes in anorexia were more severe than in other any psychiatric condition we have studied. Effects of treatments and interventions can now be evaluated, using these new brain maps as a reference," he noted.

Immediate Clinical Implications

Reached for comment, Allison Eliscu, MD, chief of the Division of Adolescent Medicine, Department of Pediatrics in the Renaissance School of Medicine at Stony Brook University in New York, said the findings have immediate implications for clinical care.

"When we talk to our patients and the parents, a lot of them focus on things that they can see, such as the way they look. It adds a lot to the conversation to be able to say: You’re obviously not seeing these changes in the brain, but they're happening and could be potentially long term if you don't start weight restoring, or if you weight restore and then continue to drop again," Eliscu told Medscape.

The findings, she said, really do highlight what anorexia can do to the brain.

"Adolescents need to know, anorexia can absolutely decrease the size of your brain in different areas; you're not just losing weight in your belly and your thighs, you’re losing weight in the brain as well and that's really concerning," said Eliscu.

The study had no commercial funding. The authors and Eliscu report no relevant conflicts of interest.

Biol Psychiatry. Published online May 31, 2022. Abstract.

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