Eating Disorders: An Evolutionary Psychoneuroimmunological Approach

Area of Science:

• Evolutionary psychology
• Psychoneuroimmunology
• Psychiatry

Background:

• Eating disorders are evolutionarily novel psychiatric conditions with high mortality rates.
• Existing hypotheses like intrasexual competition lack comprehensive explanatory power.
• The modern environment presents a unique challenge with readily available, hyper-rewarding foods.

Purpose of the Study:

• To introduce and elaborate on the mismatch hypothesis for eating disorders.
• To propose a psychoneuroimmunological model linking evolutionary pressures to proximate mechanisms.
• To explore the role of chronic stress, neuroinflammation, and the serotonergic system in eating disorders.

Main Methods:

• Review of evolutionary hypotheses for eating disorders.
• Development of a psychoneuroimmunological model.
• Analysis of the interplay between mating motives, food rewards, stress, and neuroinflammation.
• Examination of the serotonergic system's role in anorexia nervosa and dieting.

Main Results:

• The mismatch hypothesis posits an adaptive metaproblem arising from conflicting mating motives and obesogenic food availability.
• Chronic stress from this mismatch drives neuroinflammation, increasing susceptibility to OCD-like behaviors and dysphoric mood.
• Stringent dieting creates a vicious cycle of increased stress, neuroinflammation, and altered serotonin levels.

Conclusions:

• Eating disorders are influenced by variations in gut microbiota and stress responsivity, impacting neuroinflammation and serotonin.
• Effective treatments must target chronic stress, neuroinflammation, stress responsivity, and gut dysbiosis.
• Integrating ultimate evolutionary causes with proximate mechanisms offers a path to more effective interventions for eating disorders.