Changes of food-cue processing in major depressive disorder patients with decreased appetite: An event-related potential study

Appetite decrease is a common symptom in major depressive disorder (MDD). However, published research discussing the cognitive process to food stimuli in MDD patients with decreased appetite is lacking, as are objective indicators to assess their degree of appetitive loss. The current study evaluated the disparities in food-related cognition between healthy controls and MDD patients, explored the brain regions contributing to these changes, and evaluated the potential of event-related potentials for assessing appetite loss severity. A total of 149 subjects (healthy controls, n = 50; MDD patients with decreased appetite, n = 52; MDD patients without appetite change, n = 47) were included in this study. We used the Dimensional Anhedonia Rating Scale (DARS) to measure the degree of appetite decrease, and assessed their alterations in food-related cognition with the late positive potential (LPP). The standardized low-resolution brain electromagnetic tomography (sLORETA) method was used to explore the source activity of the LPP. We found the two groups of MDD patients did not differ in the disease severity, while those with appetite decrease got the lowest DARS food/drink score. And MDD patients with decreased appetite allocated fewer attentional resources to food stimuli with significantly lower LPP amplitude evoked by food in this group. Within depressed patients, LPP source activations were reduced in lingual gyrus, cuneus, inferior and middle occipital lobe, and inferior occipital gyrus in appetite-decreased patients, indicating altered occipital activity may be associated with attentional processing in MDD patients with decreased appetite. And correlation analysis revealed a moderate, positive correlation between LPP amplitude and DARS food/drink score. This study demonstrates the cognitive differences between MDD patients with appetite decrease and without appetite change, and provides a potential biomarker for evaluating the degree of appetite loss in MDD patients experiencing decreased appetite.