P ED

 

Eating disorder brain changes. Trait v state

Eating disorder brain changes can be conceptualized along a trait versus state dimension, distinguishing between enduring neurobiological vulnerabilities and reversible alterations related to the acute illness phase.

State-Related Brain Changes

State-related changes are those associated with the acute phase of illness and often normalize with recovery:

Structural Changes:

• Patients with acute anorexia nervosa (AN) show reduced gray matter volume and cortical thickness across multiple brain regions, particularly in frontal, temporal, and parietal areas. These structural deficits largely return to normal with weight restoration and clinical recovery.
• Reduced local gyrification index (LGI) has been consistently reported in acute AN, suggesting altered cortical folding patterns that may partially normalize following weight restoration.
• White matter integrity changes, particularly reduced fornix integrity, have been observed in both AN and bulimia nervosa (BN) during the acute illness state.

Functional Changes:

• Functional MRI studies show that neural responses to food stimuli and affective ratings normalize in recovered individuals, suggesting these alterations are state-dependent.
• Altered reward processing, including aberrant striatal and insular responses to food cues, appears to be state-related and changes with recovery.

Trait-Related Brain Changes

Trait-related changes persist after recovery and may represent predisposing vulnerabilities:

Structural Alterations:

• Larger left medial orbitofrontal cortex volume has been found in both ill and recovered AN patients, as well as in BN patients, suggesting this may be a trait marker. The orbitofrontal cortex is crucial for terminating food intake, and altered function could contribute to self-starvation behaviors.
• Enlarged right insula volume persists in both ill and recovered AN patients. Since the insula processes taste and interoception, this trait alteration could relate to the persistent distorted perception of body size characteristic of AN.

Functional Patterns:

• Alterations in reward circuitry, particularly involving the insula and striatum, appear to have both state and trait components. The reward system shows hypersensitivity in AN and hyporesponsivity in BN, patterns that may reflect both predisposing traits and adaptive changes to extreme eating behaviors.
• Disrupted resting-state connectivity in executive networks, the default-mode network, and the salience network appears to persist across eating disorders and may represent trait vulnerabilities.

Neurotransmitter Systems

Serotonin (5-HT) system alterations in eating disorders represent a convergence of state, trait, and developmental effects:

• Trait effects: Related to inherited variations in impulsivity and perfectionism
• State effects: Secondary to nutritional status and acute illness behaviors
• Developmental effects: Potentially long-term neurobiological consequences of early stressors

Clinical Implications

The distinction between state and trait changes has important implications:

1. Reversibility: State-related structural and functional changes can improve with treatment and weight restoration, offering hope for recovery.
2. Vulnerability markers: Trait alterations may help identify individuals at risk for developing eating disorders or experiencing relapse.
3. Treatment targets: Understanding which brain changes are modifiable (state) versus enduring (trait) can inform treatment approaches. For example, addressing malnutrition-related state changes may help normalize brain function and reduce symptom maintenance.
4. Longitudinal perspective: The interplay between trait vulnerabilities and state-dependent changes suggests that eating disorders involve both predisposing factors and illness-perpetuating mechanisms that develop over time.

Research indicates that starvation-related brain changes can disrupt reward-related function, increase neuroticism, and reinforce cognitive restraint, creating a cycle that perpetuates eating disorder symptoms. This highlights how state changes can interact with trait vulnerabilities to maintain illness behaviors.

References:

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2. Frank G. Advances from neuroimaging studies in eating disorders. CNS Spectrums. 2015; 20:391-400.https://doi.org/10.1017/s1092852915000012
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9. Yu X, Robinson L, Bobou M, Zhang Z, Banaschewski T, Barker G, Bokde A, Flor H, Grigis A, Garavan H, Gowland P, Heinz A, Brühl R, Martinot J, Martinot M-L P, Artiges E, Nees F, Orfanos D P, Lemaître H, Poustka L, Hohmann S, Holz N, Bäuchl C, Smolka M N, Stringaris A, Walter H, Whelan R, Sinclair J, Schumann G, Schmidt U, Desrivières S, Büchel C. Multimodal Investigations of Structural and Functional Brain Alterations in Anorexia and Bulimia Nervosa and Their Relationships to Psychopathology. Biological Psychiatry. 2024; 98:237-248.https://doi.org/10.1016/j.biopsych.2024.11.008